use cache repo when creating GitRepository instances

rhodecode/lib/vcs/backends/git/repository.py

@@ -207,7 +207,7 b' class GitRepository(BaseRepository):'
                 else:
                     return Repo.init(self.path)
             else:
-                return Repo(self.path)
+                return self._repo
         except (NotGitRepository, OSError), err:
             raise RepositoryError(err)