Use upstream policy.json for keystone.

Change-Id: I21a5dbcbd654c80c25469b9c268fbe7422875af5
Use upstream policy.json for cinder.

Change-Id: I53f8e2416011ae7b8cf08f130371c8f819395069
Use upstream policy.json for heat.

Change-Id: I77277a1240836fe7f68325e85c8fed683f5e19fe
Merge "Use upstream policy.json for keystone."
Merge "Use upstream policy.json for cinder."
Merge "Use upstream policy.json for heat."