rebase: do not consider extincts for divergence detection (issue5782)...
rebase: do not consider extincts for divergence detection (issue5782)
Extinct obsolete changesets cannot cause divergence upon rebase. We
compute these obsoletes without a non-obsolete successor (extincts) in
_computeobsoletenotrebased() and then filter them out from the set of
obsolete revisions to rebase before getting into _checkobsrebase() to
check for divergence candidates.