type casting of None in models.Changes to 'None' is wrong

[ReimarBauer]

By fixing #1860 with #2585 I have seen that the https://github.com/Open-MSS/MSS/blob/develop/mslib/mscolab/models.py#L210 version_name default is None. But the comparison to None https://github.com/Open-MSS/MSS/blob/develop/mslib/mscolab/file_manager.py#L466 gives not the expected result. It looks like adding waypoints stores it as "None".

In the PR I do use now .filter(str(Change.version_name) != "None")\

I don't know currently where the Type Cast happens or what's the reason.

[ReimarBauer]

ok, the casting happens at
https://github.com/Open-MSS/MSS/blob/develop/mslib/mscolab/models.py#L219

02999a0

[ReimarBauer]

The None cast needs to be undone