Correct ssl_conf logic for "legacy_server_connect"

This option is only useful for the client, but it was previously
marked as only being applicable for servers.

Correct the entry to properly mark it as client-only, and update the
s_server/s_client manuals accordingly.
Reviewed-by: NMatt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/15127)

doc/man1/openssl-s_client.pod.in

@@ -83,6 +83,7 @@ B<openssl> B<s_client>
 [B<-comp>]
 [B<-no_comp>]
 [B<-brief>]
+[B<-legacy_server_connect>]
 [B<-allow_no_dhe_kex>]
 [B<-sigalgs> I<sigalglist>]
 [B<-curves> I<curvelist>]

doc/man1/openssl-s_server.pod.in

@@ -94,7 +94,6 @@ B<openssl> B<s_server>
 [B<-serverpref>]
 [B<-legacy_renegotiation>]
 [B<-no_renegotiation>]
-[B<-legacy_server_connect>]
 [B<-no_resumption_on_reneg>]
 [B<-no_legacy_server_connect>]
 [B<-allow_no_dhe_kex>]

ssl/ssl_conf.c

@@ -684,7 +684,7 @@ static const ssl_conf_cmd_tbl ssl_conf_cmds[] = {
     SSL_CONF_CMD_SWITCH("no_ticket", 0),
     SSL_CONF_CMD_SWITCH("serverpref", SSL_CONF_FLAG_SERVER),
     SSL_CONF_CMD_SWITCH("legacy_renegotiation", 0),
-    SSL_CONF_CMD_SWITCH("legacy_server_connect", SSL_CONF_FLAG_SERVER),
+    SSL_CONF_CMD_SWITCH("legacy_server_connect", SSL_CONF_FLAG_CLIENT),
     SSL_CONF_CMD_SWITCH("no_renegotiation", 0),
     SSL_CONF_CMD_SWITCH("no_resumption_on_reneg", SSL_CONF_FLAG_SERVER),
     SSL_CONF_CMD_SWITCH("no_legacy_server_connect", SSL_CONF_FLAG_SERVER),