BUG/MEDIUM: cli: fix "show stat resolvers" and "show tls-keys"

The recent CLI reorganization managed to break these two commands
by having their parser return 1 (indicating an end of processing)
instead of 0 to indicate new calls to the io handler were needed.

Namely the faulty commits are :
  69e9644 ("REORG: cli: move show stat resolvers to dns.c")
  32af203 ("REORG: cli: move ssl CLI functions to ssl_sock.c")

The fix is trivial and there is no other loss of functionality. Thanks
to Dragan Dosen for reporting the issue and the faulty commits. The
backport is needed in 1.7.
diff --git a/src/ssl_sock.c b/src/ssl_sock.c
index 8429324..baaa0a1 100644
--- a/src/ssl_sock.c
+++ b/src/ssl_sock.c
@@ -6140,7 +6140,7 @@
 	if (!*args[2]) {
 		appctx->ctx.tlskeys.dump_all = 1;
 		appctx->io_handler = cli_io_handler_tlskeys_files;
-		return 1;
+		return 0;
 	}
 
 	if (args[2][0] == '*') {
@@ -6156,7 +6156,7 @@
 		}
 	}
 	appctx->io_handler = cli_io_handler_tlskeys_entries;
-	return 1;
+	return 0;
 }