status -r raises NameError exception

[Stuart Bishop]

16:43:07~/lp/pristine $ bzr status -r 3859..3860
bzr: ERROR: exceptions.NameError: global name 'BzrCommandError' is not defined
  at /usr/lib/python2.4/site-packages/bzrlib/status.py line 126
  in show_tree_status
16:43:11~/lp/pristine $ bzr version
bzr (bazaar-ng) 0.8.2
Copyright 2005, 2006 Canonical Development Ltd.
http://bazaar-ng.org/

bzr comes with ABSOLUTELY NO WARRANTY. bzr is free software, and
you may use, modify and redistribute it under the terms of the GNU
General Public License version 2 or later.

[John A Meinel (jameinel)]

bzr-0.9 fixes this exception to use errors.BzrCommandError()

And bzr-0.11 refined the --revision handling so that we get nicer errors all around.