Fixes in keypair handling

    Creating per user per project keypair and raising exceptions if the keys dont match
    We could have deleted the keypair and configured new but felt its better to notify which would help narrow down issues
    Also invoking teardownclass to cleanup the tenants which were missing for vm_regression testsuite which i was using for testing
    Believe other scenarios too miss the same

    ammending for vpc and in vpc we seem to use stack_user user alone for all op hence handling the same.

    Closes-Bug: #1379111

Change-Id: I56aaa2ab1d238b826d77fa0384254a5bb6e635a0
Merge "    Fixes in keypair handling"