Previously, obsoleted revs with successors in destination are completely
ignored. That caused some inconvenience when working copy is obsoleted. Most
commands avoid working copy being obsoleted, but hg pull is an exception.
This patch makes rebase able to move bookmarks or working parent for those
obsoleted revs. It does so by keeping the obsoleted revs in state and
marking them as "skipped, rebased to desired destination" during run-time.
This reverts part of the behavior change of 3b7cb3d17137 and D24.
this looks like it would be the same as on line 401