tests/test-issue1877.t

rebase: clear updatestate during rebase --abort in more cases

Previously, rebase --abort would only call update if you were on a node that had
already been rebased. This meant that if the rebase failed during the rebase of
the first commit, the working copy would be left dirty (with a .hg/updatestate
file) and rebase --abort would not have update to clean it up.

The fix is to also perform an update if you're still on the target node or on
the original working copy node (since the working copy may be dirty, we still
need to do the update). We don't want to perform an update in all cases though
because of issue4009.

A subsequent patch makes this case much more common, since it causes the entire
rebase transaction to rollback during unexpected exceptions. This causes the
existing test-rebase-abort.t to cover this case.

https://bz.mercurial-scm.org/1877

  $ hg init a
  $ cd a
  $ echo a > a
  $ hg add a
  $ hg ci -m 'a'
  $ echo b > a
  $ hg ci -m'b'
  $ hg up 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg book main
  $ hg book
   * main                      0:cb9a9f314b8b
  $ echo c > c
  $ hg add c
  $ hg ci -m'c'
  created new head
  $ hg book
   * main                      2:d36c0562f908
  $ hg heads
  changeset:   2:d36c0562f908
  bookmark:    main
  tag:         tip
  parent:      0:cb9a9f314b8b
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     c
  
  changeset:   1:1e6c11564562
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     b
  
  $ hg up 1e6c11564562
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  (leaving bookmark main)
  $ hg merge main
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg book
     main                      2:d36c0562f908
  $ hg ci -m'merge'
  $ hg book
     main                      2:d36c0562f908

  $ cd ..