[MERGE] Cleanups for fallback repos and stacking

[Vincent Ladeuil]

BB:tweak

>>>>> "jam" == John Arbash Meinel <john at arbash-meinel.com> writes:

<snip/>

    jam> === modified file 'bzrlib/remote.py'

<snip/>

    jam>      def leave_lock_in_place(self):
    jam> @@ -956,6 +956,7 @@
    jam>                  raise AssertionError(
    jam>                      "cannot cleanly remove existing _fallback_repositories")
    jam>          for fb in self._fallback_repositories:
    jam> +            assert fb.is_locked() == self.is_locked(), 'lock mismatch during _set_real'

:-)

        Vincent