[0.18.3] Train wagen ghost disappears after placing ghost belt

[AntiElitz]

When placing this blueprint, the wagon ghost disappears when placing one of the belts. Works fine if the wagon is placed by bots first instead - so it's dependent on order.

https://clips.twitch.tv/PrettyWealthyCa ... arTheThing

[boskid]

This is fixed for 0.18.30

[posila]

Just for future reference in case the fix comes back and starts to haunt us

this is some corner case with collision masks (transport belt ghost overlaps onto rolling stock collision mask) and buildability check, when reviving transport belt, there is call to removeConflictingGhostsAndCorpses which does if (!ghost->innerEntity->buildabilityCheck(BuildCheckData::simple(BuildCheckType::GhostRevive)).isBuildable()) (Entity.cpp:474) and here, rolling stock is decided it is not buildable since it has no rail under it, but it does that because it is entity ghost and is not connected to rails - rolling stock ghost is deleted