Revert "my_activity.py: Add WebRTC code review and Google code site."

This reverts https://codereview.chromium.org/1008143002
since WebRTC has now moved over to Chromium's Rietveld instance.

BUG=webrtc:3884

Review URL: https://codereview.chromium.org/1188523002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@296585 0039d316-1c4b-4281-b951-d872f2087c98

my_activity.py

@@ -84,13 +84,6 @@ rietveld_instances = [
     'requires_auth': False,
     'email_domain': 'chromium.org',
   },
-  {
-    'url': 'webrtc-codereview.appspot.com',
-    'shorturl': 'go/rtcrev',
-    'supports_owner_modified_query': True,
-    'requires_auth': False,
-    'email_domain': 'webrtc.org',
-  },
 ]
 
 gerrit_instances = [