Temporarily ignore content-owner specs in Travis

During the last 48 hours, YouTube API has being responding with
unexpected and undocumented errors to the content-owner endpoints.
Since some pull requests are waiting for tests to pass on Travis CI and
do not touch the content-owner component at all, those tests are
temporarily skipped to allow those PRs to be accepted. This will cause
code coverage to go down, but it's a temporary fix waiting for YouTube
API to work again.
Merge branch 'temporarily-skip-content-owner-specs'