_string_rev_revno may not retrun a String

[Andrey Larionov]

After installing Trac 0.11.4 with latest checkout of trac-bzr and bzr 1.13.1 cant display browser. _parse_rev try to call .isdigit on rev assuming what it recives string, but recives int. Problem in _string_rev_revno.
=== modified file 'tracbzr/backend.py'
--- tracbzr/backend.py 2009-03-26 15:14:48 +0000
+++ tracbzr/backend.py 2009-04-11 17:58:54 +0000
@@ -199,7 +199,7 @@
         if branch_name != "":
             return '%s,%s' % (branch_name, revno)
         else:
- return revno
+ return '%s' % revno

     def _parse_rev(self, rev):
         """Translate a trac rev string into a (branch, revid) tuple.