Uses oslo's deprecated decorator; removes ours

bp: deprecated-as-of-icehouse
Change-Id: Ideeaca14ccd8cbf7c37b096338324b5bc0e021d6
Policy based domain isolation can't be defined.

Policy based domain isolation is not possible on token
APIs due to lack of domain_id in policy_dict for API target

Closes-Bug: 1233874
Closes-Bug: 1251048

Change-Id: I855ec8ff4899ba3797a2e2bb23945ab4b23d2bea
Merge "Uses oslo's deprecated decorator; removes ours"
Merge "Policy based domain isolation can't be defined."