MEDIUM: check: server states and weight propagation re-work

The server state and weight was reworked to handle
"pending" values updated by checks/CLI/LUA/agent.
These values are commited to be propagated to the
LB stack.

In further dev related to multi-thread, the commit
will be handled into a sync point.

Pending values are named using the prefix 'next_'
Current values used by the LB stack are named 'cur_'
diff --git a/src/haproxy.c b/src/haproxy.c
index fc99225..2fa00a4 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -732,7 +732,7 @@
 			chunk_printf(&trash,
 			             "SIGHUP: Server %s/%s is %s. Conn: %d act, %d pend, %lld tot.",
 			             p->id, s->id,
-			             (s->state != SRV_ST_STOPPED) ? "UP" : "DOWN",
+			             (s->cur_state != SRV_ST_STOPPED) ? "UP" : "DOWN",
 			             s->cur_sess, s->nbpend, s->counters.cum_sess);
 			Warning("%s\n", trash.str);
 			send_log(p, LOG_NOTICE, "%s\n", trash.str);