MINOR: mailers: make it possible to configure the connection timeout

This patch introduces a configurable connection timeout for mailers
with a new "timeout mail <time>" directive.

Acked-by: Simon Horman <horms@verge.net.au>
diff --git a/src/checks.c b/src/checks.c
index 4d3b393..35fd020 100644
--- a/src/checks.c
+++ b/src/checks.c
@@ -3108,9 +3108,7 @@
 
 		LIST_INIT(&q->email_alerts);
 
-		check->inter = DEF_MAILALERTTIME; /* XXX: Would like to Skip to the next alert, if any, ASAP.
-					     * But need enough time so that timeouts don't occur
-					     * during tcp check procssing. For now just us an arbitrary default. */
+		check->inter = p->email_alert.mailers.m->timeout.mail;
 		check->rise = DEF_AGENT_RISETIME;
 		check->fall = DEF_AGENT_FALLTIME;
 		err_str = init_check(check, PR_O2_TCPCHK_CHK);