Support persistent-http(s) review urls

Change-Id: I8e0065685c968dfa9dc26bcdb6ee2fa14019c509
diff --git a/git_config.py b/git_config.py
index b4145e8..e789be2 100644
--- a/git_config.py
+++ b/git_config.py
@@ -566,6 +566,8 @@
         return None
 
       u = self.review
+      if u.startswith('persistent-'):
+        u = u[len('persistent-'):]
       if u.split(':')[0] not in ('http', 'https', 'sso'):
         u = 'http://%s' % u
       if u.endswith('/Gerrit'):