Ticket 48665 - Fix RHEL6 test compatibility issues
Bug description: It is impossible to use inst.whoami_s() on RHEL6.
It throws PROTOCOL_ERROR: 'unsupported extended operation'.
Fix description: Use a search to verify that the server has not
crushed.
https://fedorahosted.org/389/ticket/48665
Reviewed by: nhosoi (Thanks!)