BUG/MINOR: tcpcheck: conf parsing error when no port configured on server and last rule is a CONNECT with no port

Current configuration parsing is permissive in such situation:
A server in a backend with no port conigured on the IP address
statement, no 'port' parameter configured and last rule of a tcp-check
is a CONNECT with no port.

The current code currently parses all the rules to validate a port is
well available, but it misses the last one, which means such
configuration is valid:

  backend b
   option tcp-check
   tcp-check connect port 8444
   tcp-check connect
   server s 127.0.0.1 check

the second connect tentative is sent to port '0'...

Current patch fixes this by parsing the list the right way, including
the last rule.

backport status: 1.6 and above
(cherry picked from commit 3dd73bea64dcbaa04858cb256c2230dbf3da58e8)
(cherry picked from commit 5a0cf2c0e861d18d744da927d613532e6da95d37)
diff --git a/src/server.c b/src/server.c
index bc74944..f8c43e2 100644
--- a/src/server.c
+++ b/src/server.c
@@ -1633,7 +1633,7 @@
 					/* scan the tcp-check ruleset to ensure a port has been configured */
 					l = &newsrv->proxy->tcpcheck_rules;
 					list_for_each_entry(n, l, list) {
-						r = (struct tcpcheck_rule *)n->list.p;
+						r = (struct tcpcheck_rule *)n->list.n;
 						if ((r->action == TCPCHK_ACT_CONNECT) && (!r->port)) {
 							Alert("parsing [%s:%d] : server %s has neither service port nor check port, and a tcp_check rule 'connect' with no port information. Check has been disabled.\n",
 							      file, linenum, newsrv->id);