CLEANUP: cli: remove undocumented "set ssl tls-keys" command

The documented "set ssl tls-key" command must be used instead.

This is for 1.8 only.
diff --git a/src/ssl_sock.c b/src/ssl_sock.c
index 45bb906..39063ec 100644
--- a/src/ssl_sock.c
+++ b/src/ssl_sock.c
@@ -7907,7 +7907,6 @@
 #if (defined SSL_CTRL_SET_TLSEXT_TICKET_KEY_CB && TLS_TICKETS_NO > 0)
 	{ { "show", "tls-keys", NULL }, "show tls-keys [id|*]: show tls keys references or dump tls ticket keys when id specified", cli_parse_show_tlskeys, NULL },
 	{ { "set", "ssl", "tls-key", NULL }, "set ssl tls-key [id|keyfile] <tlskey>: set the next TLS key for the <id> or <keyfile> listener to <tlskey>", cli_parse_set_tlskeys, NULL },
-	{ { "set", "ssl", "tls-keys", NULL }, NULL, cli_parse_set_tlskeys, NULL },
 #endif
 	{ { "set", "ssl", "ocsp-response", NULL }, NULL, cli_parse_set_ocspresponse, NULL },
 	{ { NULL }, NULL, NULL, NULL }