Fix some leaks of groups/raids (#1242)

These cases probably are exceedingly rare, but they still need to be
accounted for. (As in, I don't think anyone has run into these cases too
often to cause problems)

zone/client_packet.cpp

@@ -561,8 +561,9 @@ void Client::CompleteConnect()
 				entity_list.AddRaid(raid, raidid);
 				raid->LoadLeadership(); // Recreating raid in new zone, get leadership from DB
 			}
-			else
-				raid = nullptr;
+			else {
+				safe_delete(raid);
+			}
 		}
 		if (raid) {
 			SetRaidGrouped(true);