MINOR: appctx/cli: remove the "tlskeys" entry from the appctx union

This one now migrates to the general purpose cli.p0 for the ref pointer,
cli.i0 for the dump_all flag and cli.i1 for the dump_keys_index. A few
comments were added.

The applet.h file doesn't depend on openssl anymore. It's worth noting
that the previous dependency was accidental and only used to work because
all files including this one used to have openssl included prior to
loading this file.
diff --git a/src/ssl_sock.c b/src/ssl_sock.c
index 0a06adb..9628c5d 100644
--- a/src/ssl_sock.c
+++ b/src/ssl_sock.c
@@ -6037,6 +6037,9 @@
 	return cli_io_handler_tlskeys_files(appctx);
 }
 
+/* dumps all tls keys. Relies on cli.i0 (non-null = only list file names), cli.i1
+ * (next index to be dumped), and cli.p0 (next key reference).
+ */
 static int cli_io_handler_tlskeys_files(struct appctx *appctx) {
 
 	struct stream_interface *si = appctx->owner;
@@ -6059,40 +6062,40 @@
 			return 0;
 		}
 
-		appctx->ctx.tlskeys.dump_keys_index = 0;
-
 		/* Now, we start the browsing of the references lists.
 		 * Note that the following call to LIST_ELEM return bad pointer. The only
 		 * available field of this pointer is <list>. It is used with the function
 		 * tlskeys_list_get_next() for retruning the first available entry
 		 */
-		if (appctx->ctx.tlskeys.ref == NULL) {
-			appctx->ctx.tlskeys.ref = LIST_ELEM(&tlskeys_reference, struct tls_keys_ref *, list);
-			appctx->ctx.tlskeys.ref = tlskeys_list_get_next(appctx->ctx.tlskeys.ref, &tlskeys_reference);
+		if (appctx->ctx.cli.p0 == NULL) {
+			appctx->ctx.cli.p0 = LIST_ELEM(&tlskeys_reference, struct tls_keys_ref *, list);
+			appctx->ctx.cli.p0 = tlskeys_list_get_next(appctx->ctx.cli.p0, &tlskeys_reference);
 		}
 
 		appctx->st2 = STAT_ST_LIST;
 		/* fall through */
 
 	case STAT_ST_LIST:
-		while (appctx->ctx.tlskeys.ref) {
-			int head = appctx->ctx.tlskeys.ref->tls_ticket_enc_index;
+		while (appctx->ctx.cli.p0) {
+			struct tls_keys_ref *ref = appctx->ctx.cli.p0;
+			int head = ref->tls_ticket_enc_index;
 
 			chunk_reset(&trash);
-			if (appctx->io_handler == cli_io_handler_tlskeys_entries && appctx->ctx.tlskeys.dump_keys_index == 0)
+			if (appctx->io_handler == cli_io_handler_tlskeys_entries && appctx->ctx.cli.i1 == 0)
 				chunk_appendf(&trash, "# ");
-			if (appctx->ctx.tlskeys.dump_keys_index == 0)
-				chunk_appendf(&trash, "%d (%s)\n", appctx->ctx.tlskeys.ref->unique_id,
-				              appctx->ctx.tlskeys.ref->filename);
+
+			if (appctx->ctx.cli.i1 == 0)
+				chunk_appendf(&trash, "%d (%s)\n", ref->unique_id, ref->filename);
+
 			if (appctx->io_handler == cli_io_handler_tlskeys_entries) {
-				while (appctx->ctx.tlskeys.dump_keys_index < TLS_TICKETS_NO) {
+				while (appctx->ctx.cli.i1 < TLS_TICKETS_NO) {
 					struct chunk *t2 = get_trash_chunk();
 
 					chunk_reset(t2);
 					/* should never fail here because we dump only a key in the t2 buffer */
-					t2->len = a2base64((char *)(appctx->ctx.tlskeys.ref->tlskeys + (head + 2 + appctx->ctx.tlskeys.dump_keys_index) % TLS_TICKETS_NO),
+					t2->len = a2base64((char *)(ref->tlskeys + (head + 2 + appctx->ctx.cli.i1) % TLS_TICKETS_NO),
 					                   sizeof(struct tls_sess_key), t2->str, t2->size);
-					chunk_appendf(&trash, "%d.%d %s\n", appctx->ctx.tlskeys.ref->unique_id, appctx->ctx.tlskeys.dump_keys_index, t2->str);
+					chunk_appendf(&trash, "%d.%d %s\n", ref->unique_id, appctx->ctx.cli.i1, t2->str);
 
 					if (bi_putchk(si_ic(si), &trash) == -1) {
 						/* let's try again later from this stream. We add ourselves into
@@ -6101,9 +6104,9 @@
 						si_applet_cant_put(si);
 						return 0;
 					}
-					appctx->ctx.tlskeys.dump_keys_index++;
+					appctx->ctx.cli.i1++;
 				}
-				appctx->ctx.tlskeys.dump_keys_index = 0;
+				appctx->ctx.cli.i1 = 0;
 			}
 			if (bi_putchk(si_ic(si), &trash) == -1) {
 				/* let's try again later from this stream. We add ourselves into
@@ -6113,12 +6116,11 @@
 				return 0;
 			}
 
-			if (appctx->ctx.tlskeys.dump_all == 0) /* don't display everything if not necessary */
+			if (appctx->ctx.cli.i0 == 0) /* don't display everything if not necessary */
 				break;
 
 			/* get next list entry and check the end of the list */
-			appctx->ctx.tlskeys.ref = tlskeys_list_get_next(appctx->ctx.tlskeys.ref, &tlskeys_reference);
-
+			appctx->ctx.cli.p0 = tlskeys_list_get_next(appctx->ctx.cli.p0, &tlskeys_reference);
 		}
 
 		appctx->st2 = STAT_ST_FIN;
@@ -6133,23 +6135,22 @@
 
 #endif
 
+/* sets cli.i0 to non-zero if only file lists should be dumped */
 static int cli_parse_show_tlskeys(char **args, struct appctx *appctx, void *private)
 {
-	appctx->ctx.tlskeys.dump_all = 0;
 	/* no parameter, shows only file list */
 	if (!*args[2]) {
-		appctx->ctx.tlskeys.dump_all = 1;
+		appctx->ctx.cli.i0 = 1;
 		appctx->io_handler = cli_io_handler_tlskeys_files;
 		return 0;
 	}
 
 	if (args[2][0] == '*') {
 		/* list every TLS ticket keys */
-		appctx->ctx.tlskeys.ref = NULL;
-		appctx->ctx.tlskeys.dump_all = 1;
+		appctx->ctx.cli.i0 = 1;
 	} else {
-		appctx->ctx.tlskeys.ref = tlskeys_ref_lookup_ref(args[2]);
-		if (!appctx->ctx.tlskeys.ref) {
+		appctx->ctx.cli.p0 = tlskeys_ref_lookup_ref(args[2]);
+		if (!appctx->ctx.cli.p0) {
 			appctx->ctx.cli.msg = "'show tls-keys' unable to locate referenced filename\n";
 			appctx->st0 = CLI_ST_PRINT;
 			return 1;
@@ -6162,6 +6163,8 @@
 
 static int cli_parse_set_tlskeys(char **args, struct appctx *appctx, void *private)
 {
+	struct tls_keys_ref *ref;
+
 	/* Expect two parameters: the filename and the new new TLS key in encoding */
 	if (!*args[3] || !*args[4]) {
 		appctx->ctx.cli.msg = "'set ssl tls-key' expects a filename and the new TLS key in base64 encoding.\n";
@@ -6169,8 +6172,8 @@
 		return 1;
 	}
 
-	appctx->ctx.tlskeys.ref = tlskeys_ref_lookup_ref(args[3]);
-	if(!appctx->ctx.tlskeys.ref) {
+	ref = tlskeys_ref_lookup_ref(args[3]);
+	if (!ref) {
 		appctx->ctx.cli.msg = "'set ssl tls-key' unable to locate referenced filename\n";
 		appctx->st0 = CLI_ST_PRINT;
 		return 1;
@@ -6183,8 +6186,8 @@
 		return 1;
 	}
 
-	memcpy(appctx->ctx.tlskeys.ref->tlskeys + ((appctx->ctx.tlskeys.ref->tls_ticket_enc_index + 2) % TLS_TICKETS_NO), trash.str, trash.len);
-	appctx->ctx.tlskeys.ref->tls_ticket_enc_index = (appctx->ctx.tlskeys.ref->tls_ticket_enc_index + 1) % TLS_TICKETS_NO;
+	memcpy(ref->tlskeys + ((ref->tls_ticket_enc_index + 2) % TLS_TICKETS_NO), trash.str, trash.len);
+	ref->tls_ticket_enc_index = (ref->tls_ticket_enc_index + 1) % TLS_TICKETS_NO;
 
 	appctx->ctx.cli.msg = "TLS ticket key updated!";
 	appctx->st0 = CLI_ST_PRINT;