The current Google client is not up to date.

The client is using deprecated scope, for example, search for https://www.googleapis.com/auth/userinfo.email

https://developers.google.com/+/api/auth-migration#oauth2login mentions that it is now deprecated.

This deprecated API is planned to be removed the 20th April, 2015.

PS: there may be other calls to the Google API in Moodle that are not using this client. So look into the all Moodle core code for the deprecated scopes.