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 instead.
It caused breakages in infinitepush, because phases handling is not skipped even during
infinitepush. This diff fixes it.