rebase: properly abort when destination is public (issue4896) After rebasing a set of changes onto a public changeset and having the first one be skipped, if you try to abort, the operation fails. This fix adds a check to disallow the target rev into the dstates list within the abort function. This list is checked for immutable states before the rest of abort does its thing.

bookmarks: don't deactivate on no-op update (issue4901)