Fixed map-server errors from Cloud Kill (fixes #1553)

* Resolves the Cloud Kill status trying to add a timer to a dead target.

src/map/status.c

@@ -12609,7 +12609,8 @@ int status_change_timer(int tid, unsigned int tick, int id, intptr_t data)
 				map_freeblock_lock();
 				dounlock = true;
 				skill_attack(skill_get_type(status_sc2skill(type)), src, unit_bl, bl, SO_CLOUD_KILL, sce->val1, tick, 0);
-				sc_timer_next(500 + tick, status_change_timer, bl->id, data);
+				if (!status_isdead(bl))
+					sc_timer_next(500 + tick, status_change_timer, bl->id, data);
 			}
 		}
 		break;