This way, tests will appear as from 'extra' module.
Besides the move, some minor changes:
- add missing self.qc.unlock_db() in create_vms()
- suffix per-template tests with template name
QubesOS/qubes-issues#1800
A simple test which checks if the device is visible there at all.
Device set with QUBES_TEST_PCIDEV env variable is used - it should be
some unimportant device which can be freely detached from dom0.
QubesOS/qubes-issues#1659
