Skip some activation key tests due to BZ 1127335

Elasticsearch is used to index new activation keys when they are created.
Unfortunately, elasticsearch cannot keep up when the system is under heavy load.
Make `ActivationKey.read_raw` only re-try a read upon receiving a 404 if
bugzilla bug 1127335 is open. Add the the `skip_if_bug_open` decorator to all
appropriate tests in module `test_activationkey`.
Merge pull request #1521 from Ichimonji10/test-activationkey

Skip some activation key tests due to BZ 1127335
Improve UI logout

Make the browser window scroll to top to ensure that logout menu is
visible.

Bonus: some formatting love
Merge pull request #1525 from elyezer/improve-ui-logout

Improve UI logout
Skip UI test_remove_prd due to a bug
Merge pull request #1526 from elyezer/skip-del-product-test

Skip UI test_remove_prd due to a bug