Fix typo resulting in a crash on some systems

See http://www.cplusplus.com/reference/vector/vector/reserve/ for reference

Thanks to Grz3s for providing the crash-log

src/game/MiscHandler.cpp

@@ -1533,7 +1533,7 @@ void WorldSession::HandleRequestHotfix(WorldPacket& recv_data)
     count = recv_data.ReadBits(23);
 
     std::vector<ObjectGuid> guids;
-    guids.reserve(count);
+    guids.resize(count);
 
     for (uint32 i = 0; i < count; ++i)
         recv_data.ReadGuidMask<0, 4, 7, 2, 5, 3, 6, 1>(guids[i]);