(QE-603) RSPEC_DESTROY and RSPEC_NO_PROVISION need to be clarified

- using RS_DESTROY=no for not destroying boxes post-test
- using RS_PROVISION=no for not provisioning boxes before tests
Merge pull request #8 from anodelman/fix-env-vars

(QE-603) RSPEC_DESTROY and RSPEC_NO_PROVISION need to be clarified