Update omniauth-google-oauth2 gem
What does this MR do?
This PR updates google omniauth gem.
Why was this MR needed?
This is needed, because google deprecates some API on Sept, 1st.
All tests pass, but I still have to test and update documentation in https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/integration/google.md
Contacts API" and "Google+ API need to be enabled
This need to be stated in the update guide (7.1 to 7.2), as well as (6.0 to 7.2)
This fixes #512 (closed)