Change logic of establishing FortifiedUnits on save

[fire-eggs]

Microprose has special units very_rarely in cities (loaded as 'Fortified Units' in CivOne).

The CivOne save logic always establishes FortifiedUnits. This seems incorrect: CivOne should avoid creating FortifiedUnits, until such time as someone determines the real reason for Microprose doing so.

[fire-eggs]

Question: save appears to be failing to take into account the possibility that a unit might be in the process of fortifying at the time of save. I.e. on save, getting an automatic fortify complete.

See Extensions.cs, GetCityData.