Tolerate set_admin_password not implemented.

Allow skipping of password test if this action
is not implemented by the virt driver.

New variable was added to devstack gate in https://review.openstack.org/#/c/10215/1

This will allow the following nova patch to be gated:

https://review.openstack.org/10130

Change-Id: I0ebd34c74bd6a4f0a31fb29f38acdbf060c64617
5 files changed