Check for bug with direct URL access

This test tests one of occurences in BZ#1093345. For the second one, no pages coverage is provided yet.

* extends the requests coverage a little bit to be able to work with the request in the test.
* adds `cfme.fixtures.pytest_selenium.on_cfme_page()` function for checking whether we really are somewhere in CFME.
* adds test for direct access on request. It uses provision with high number of machines (and no automate role to be sure), so it won't get approved, then it access it directly and then it deletes it.

TO TEST:
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`py.test -v -k test_services_request_direct_url`