[2.0.50] smart belt bug #0009

[pantabo1]

The issue here i think is twofold:
1. the underground in front of the splitter is treated as being connected to the splitter which results in the underground being added in the first place
2. it both downgrades the existing underground and then places and additional underground.


I think i would prefer / expected to get an underground that results in what is called "belt-weaving", this assumes that the splitter treating the underground in front of it being a connection to it is unchangeable.

[Loewchen]

Add a bug description to the title please, see 3638.