Add pre_test_hook.sh for devstack tempest gates.

Pre-test hook is called before executing tempest tests
in the gate. Before tempest tests are run, this script
adds necessary rbac parameters to tempest.conf.

Adopted from [0].

[0] https://github.com/openstack/manila/blob/master/contrib/ci/post_test_hook.sh

Change-Id: I67d6a820cdb2406e76603a598324fab1f9403799
1 file changed