I (wrongly) assumed in rP22456 that not giving a default value to the ticket's m_Type variable was fine since we always assigned it a value before actually using it (in RequestShort/LongPath), however I failed to anticipate that we might serialise before that gets called, and that then a garbage value in the enum could make serialisation fail.

This fixes it by giving the type a default value.

Reported by @gameboy, confirmed by @Angen, see https://code.wildfiregames.com/D1907#86396

Save a game with some units that never moved and notice it doesn't crash on VS13 anymore (possibly also other systems - this is UB so potentially tricky to reproduce)