Make Rietveld RPC work with service accounts for public instances.

R=pgervais@chromium.org, hinoka@chromium.org
BUG=489569

Review URL: https://codereview.chromium.org/1145313002.

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@295723 0039d316-1c4b-4281-b951-d872f2087c98

rietveld.py

@@ -564,7 +564,9 @@ class JwtOAuth2Rietveld(Rietveld):
       private_key_password = 'notasecret'
 
     self.url = url.rstrip('/')
-    bot_url = self.url + '/bots'
+    bot_url = self.url
+    if self.url.endswith('googleplex.com'):
+      bot_url = self.url + '/bots'
 
     with open(client_private_key_file, 'rb') as f:
       client_private_key = f.read()