Add _spec to feature specs missing it.

There were feature specs missing the _spec.rb at the end. This changes that and
fixes the specs that were not passing.

Note: in order to get the change_ccla_invitation_roles_spec, had to adjust the
organization_invitations_controller to support single invitations being updated.
Make User OAuth expiration spec deterministic.
Sleep between Change CCLA role feature specs.

To try and make sure that the page does not refresh before the ajax call is
completed, add sleep 5. This should be removed eventually for a more elegant
solution.
Merge pull request #502 from opscode/improve_feature_spec_coverage

Improve Feature Spec Coverage