message: Fix misuse of StorableResources::operator+
diff: @@ -111,7 +111,7 @@ void MineFacility::think()
  ore.resources[3] = mMine->pull(Mine::OreType::ORE_COMMON_METALS, pull_count(this, 3));
  }
  - storage() + ore;
  + storage() = storage() + ore;
  }
  else if (!isIdle())
  {
  