qa_crowbarsetup.sh: Add support for susecloud5/remove 2.0

Cloud 2.0 is EOL, so we don't need to have further support
for it. Extend the cases for Cloud 5 alongway.
qa_crowbarsetup.sh: Remove get_crowbarnodes

This function was only used in one place, and not invoked
at the right time to actually do something.