remote-bzr: update working tree upon pushing

A 'git push' doesn't update the working directory on the remote, but
a 'bzr push' does.  Teach the remote helper for bzr to update the
working tree on the bzr side upon pushing via the "export" command.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/remote-helpers/git-remote-bzr

@@ -571,6 +571,8 @@ def do_export(parser):
             repo.generate_revision_history(revid, marks.get_tip('master'))
             revno, revid = repo.last_revision_info()
             peer.import_last_revision_info_and_tags(repo, revno, revid)
+            wt = peer.bzrdir.open_workingtree()
+            wt.update()
         print "ok %s" % ref
     print