BUG/MINOR: server: free srv.lb_nodes in free_server

lb_nodes is allocated for servers using lb_chash (balance random or
hash-type consistent).

It can be backported up to 1.8.

(cherry picked from commit fb247946a1b0a6dc6b1e6b27631adf1ef40c0ee3)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
[Cf: Patch applied on haproxy.c because servers are freed in deinit()]
diff --git a/src/haproxy.c b/src/haproxy.c
index 5da563b..f55a97b 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -2670,6 +2670,7 @@
 			free(s->available_conns);
 			free(s->curr_idle_thr);
 			free(s->resolvers_id);
+			free(s->lb_nodes);
 
 			if (s->use_ssl == 1 || s->check.use_ssl == 1 || (s->proxy->options & PR_O_TCPCHK_SSL)) {
 				if (xprt_get(XPRT_SSL) && xprt_get(XPRT_SSL)->destroy_srv)