Do hangups only after server states have been updated

The hangup code was refactored into a common function which should only be
used after the server states have been updated. This will remove erroneus
connections to already failed servers.

server/modules/monitor/ndbclustermon.c

@@ -447,6 +447,8 @@ monitorMain(void *arg)
             }
             ptr = ptr->next;
         }
+
+        mon_hangup_failed_servers(mon);
     }
 }