pushrebase: handle pushing phases through separate bundle2 part
In 537de0b14030868e3e850ae388b08f88cabc88e8 upstream hg commit phase pushes
started to use separate bundle2 part. Because of that:
- pushkey hook is not called when updating phases.
- pushkey bundle2 part doesn't process phases anymore, 'phase-heads' part do
It caused breakages in pushrebase. This diff fixes it.
Run tests test-pushrebase* and test-treemanifest*
Differential Revision: https://phab.mercurial-scm.org/D1204