OpenID: Remove support for Google Accounts

From May 19, 2014[1] Google is no longer allowing new servers to use
OpenID API to authenticate user accounts.  From April 20, 2015 Google
will shut down the OpenID service.

Delete Google Account suggestion from the web interface.

[1] https://developers.google.com/+/api/auth-migration#timetable

Change-Id: Idcf4e5a528e574c0042c897db87ea821fbf89315
6 files changed