Fail create if validation flags do not agree

This makes us sanity check the wait_until, validateable, and
valiadation_resources flags we get in create_test_server(). Specifying
wait_until='SSHABLE' without the other two will silently not actually
wait for the server to be sshable.

Help make this harder to do by making create_server in the volumes
base class ensure we pass validation_resources for tests that
request SSHABLE.

Note this also includes a change to get_class_validation_resources()
to make sure it returns an empty dict just like
get_test_validation_resources() does if/when CONF has validation
disabled.

Change-Id: Ic8ae7bb322eaf1294d48d5f5242365bec5e863e2
5 files changed