#2 False errors when cascading conflicts

[Muriel Salvan]

When cascading conflicts, Shortcuts are translated but give errors doing so.

1. Rename a Tag getting conflict into another one: conflict dialog appears
2. Rename it in the conflict dialog to make it conflict with a third one, choose to merge using new values: a second conflict dialog appears
3. Merge using new values. The 3 Tags will be merged, but the translation of Shortcuts from the first one will have an error: !!! Shortcut Xxxx is tagged with Tag1, which does not exist in the known tags.