Add test coverage of existing hypervisors policies
Add test coverage of existing hypervisors policies

Current tests do not have good test coverage of existing policies.
Either tests for policies do not exist or if they exist then they
do not cover the actual negative and positive testing.

For Example, if any policy with default rule as admin only then
test should verify:
- policy check pass with context having admin or server owner
- policy check fail with context having non-admin and not server owner

As discussed in policy-defaults-refresh, to change the policies
with new default roles and scope_type, we need to have the enough
testing coverage of existing policy behavior.

When we will add the scope_type in policies or new default roles,
then these test coverage will be extended to adopt the new changes
and also make sure we do not break the existing behavior.

This commit covers the testing coverage of existing hypervisors policies.

Partial implement blueprint policy-defaults-refresh

Change-Id: Ieb5e27ccec000f6d6bb598aa00a4a17e0f334aad

klmitch/nova,klmitch/nova,klmitch/nova,openstack/nova,mahak/nova,mahak/nova,openstack/nova,mahak/nova,openstack/nova,klmitch/nova