5.0.1 Change not existing tests classes in murano test

We try to invoke non existing tests here,
in part run ostf.
Change murano ostf test class path.
Also delete unused create keypair method

Change-Id: Iadcc83a72f5cb9071be3838e12d03a6537cd213e
Related-Bug: #1320181
(cherry picked from commit aa0d05053d044508b97b8ab5501aa950cbc5c75c)