[Review] Request from 'wstephenson' @ 'SUSE/connect/review_140915_fix_failing_ci_tests_2193'

Please review the following changes:
  * b01719a Clean comments
  * 05d0a40 Fully qualify class name
  * e219a8d block not method call
  * 758bdb9 Clean up by removing local credentials after test
  * c147403 Match error message
  * 3700ccf Deregister on SCC only
  * ae103a4 Remove tag locking libzypp
I'd call that I deregister the system.