Merge branch 'fix/gitlab-omniauth-issue' into 'master'

attempting to fix omniauth problem

Attempt to fix https://gitlab.com/gitlab-org/gitlab-ce/issues/3361

See merge request !2876

app/controllers/oauth/authorizations_controller.rb

@@ -7,6 +7,7 @@ class Oauth::AuthorizationsController < Doorkeeper::AuthorizationsController
     if pre_auth.authorizable?
       if skip_authorization? || matching_token?
         auth = authorization.authorize
+        session.delete(:user_return_to)
         redirect_to auth.redirect_uri
       else
         render "doorkeeper/authorizations/new"