Fixes policy rules in neutron containing the keyword tenant_id.

The owner policy in neutron's policy.json is "tenant_id:%(tenant_id)s".
Currently, the rbac_role_converter does not populate the target dict,
responsible for providing oslo policy with as much information
about the target or user performing an action as possible, with
the key 'tenant_id'. Consequently, the rules containing the format
outlined above fail.

This patch adds 'tenant_id' as well as 'network:tenant_id' to the
target dict, in order to work with neutron's policy.json.

Change-Id: Iecf30d714ed0e9ebde2bff6013551accdf250cef
Closes-Bug: #1661062
3 files changed