totemsrp: Enhance mcast failure detection

memb_state_gather_enter increase stats.continuous_gather only if
previous state was gather also. This should happen only if multicast is
not working properly (local firewall in most cases) and not if many
nodes joins at one time.

Signed-off-by: Jan Friesse <jfriesse@redhat.com>
Reviewed-by: Angus Salkeld <asalkeld@redhat.com>
(cherry picked from commit 61d83cd719bcc93a78eb5c718a138b96c325cc3e)

exec/totemsrp.c

@@ -1881,7 +1881,13 @@ static void memb_state_gather_enter (
 
 	instance->memb_state = MEMB_STATE_GATHER;
 	instance->stats.gather_entered++;
-	instance->stats.continuous_gather++;
+
+	if (gather_from == 3) {
+		/*
+		 * State 3 means gather, so we are continuously gathering.
+		 */
+		instance->stats.continuous_gather++;
+	}
 
 	if (instance->stats.continuous_gather > MAX_NO_CONT_GATHER) {
 		log_printf (instance->totemsrp_log_level_warning,