Fix log message on exception in setUpClass

This commit fixes an issue with the log messages printed when an
arbitrary exception is raised during setUpClass. Previously the
variables were provided in the wrong order causing the log message
to be confusing.

Change-Id: Ie3682284905f0d31c801aac731ae843fae0fd314
Refactor custom matchers

This reduces the complexity by grouping checks

Change-Id: Iabdbd7cb50beb869409289918aa15005ebfe6e9b
Merge "Fix log message on exception in setUpClass"
Merge branch 'master' of https://github.com/openstack/tempest