Clean up reflog unreachability pruning decision
Clean up reflog unreachability pruning decision

This clarifies the pruning rules for unreachable commits by having a
separate helpder function for the unreachability decision.

It's preparation for actual bigger changes to come to speed up the
decision when the reachability calculations become a bottleneck.

Signed-off-by: Linus Torvalds <69652caca27c8b940640ad396ab71f93cacec34f@linux-foundation.org>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git