Force cache update on error

The gitdb is probably not able to detect changes here, so let's force it
to reread the data.

Issue #449
Signed-off-by: Michal Čihař <michal@cihar.com>

weblate/trans/models/subproject.py

@@ -404,7 +404,7 @@ class SubProject(models.Model, PercentMixin, URLMixin, PathMixin):
         except ODBError:
             # Try to reread git database in case our in memory object is not
             # up to date with it.
-            self.git_repo.odb.update_cache()
+            self.git_repo.odb.update_cache(True)
             return self.git_repo.commit('origin/%s' % self.branch)
 
     def get_repo_url(self):