Cleanup fixup.
	- VM instance cleanup steps are skipped, if VM instance was deleted before cleanup.
	- Line 639: Nova delete argument changed from "Instance name" to "Instance id".
	- Line 647: Nova volume-delete argument changed from "Volume name" to "Volume id", deletion is performed only if this volume still exists in moment of performing "volume-delete".
Merge pull request #281 from MirantisDellCrowbar/bug/smoketest_cleanup_fix/release/hydrogen/master

Cleanup fixup.