Pass the actual target in os-agents policy
Pass the actual target in os-agents policy

Currently if target is not passed in context.can(),
it use defauls target which is context.user_id, context.project_id.
These defaults target are not useful as it pass the
context's user_id and project_id only which means we tell
oslo policy to verify the context data with context data.

This commit pass the actual target for os-agents policies
which is empty dict because policy rule is system scoped rather
than project, so the token scope check deals with the required
target checking.

Partial implement blueprint policy-defaults-refresh

Change-Id: I3dc3af38ee40ad49090a64d2f6e9121067c84a05

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