[DRE-maint] ruby-omniauth-google-oauth2 is marked for autoremoval from testing

[Debian testing autoremoval watch]

ruby-omniauth-google-oauth2 0.4.1-1 is marked for autoremoval from testing on 2016-10-11

It (build-)depends on packages with these RC bugs:
835693: ruby-oauth2: FTBFS: ERROR: Test "ruby2.3" failed: Failure/Error: expect { subject.header('get', 'this-is-not-valid') }.to raise_error(ArgumentError)