"bzr commit" does not trigger DBus signal for recent branch formats

[James Henstridge]

While testing bzr-dbus with bzr-1.2, I noticed that no DBus "Revision" signal was being broadcast when I committed to a pack format branch. It seems that the "set_rh" hook was not being called.

The set_revision_history() method is not being called for branch formats newer than dirstate-tags during commit, so bzr-dbus misses the branch change. I guess it should be changed to listen to a different set of hooks (some combination of post_commit, post_uncommit, post_pull and post_push).

On IRC Aaron suggested that a bzr hook for set_revision_info() might be appropriate.

[James Henstridge (jamesh)]

As of r3361, bzr has a post_change_branch_tip hook that could be used to fix this bug.

[James Henstridge (jamesh)]

The attached branch uses the post_change_branch_tip hook in preference to set_rh if it is available. If we don't care about older versions of bzr, it'd be cleaner to just use the new hook unconditionally.