Don't persist rev event when deleting access token
Don't persist rev event when deleting access token

This is no longer needed since the token provider API will
rebuild the token context at validation time. The revocation event
is not needed and we no longer need to store it.

Change-Id: I4dc766981a29b0afd0a44718c1c5d81155163982
partial-bug: 1671887

rajalokan/keystone,ilay09/keystone,rajalokan/keystone,openstack/keystone,openstack/keystone,mahak/keystone,ilay09/keystone,openstack/keystone,ilay09/keystone,mahak/keystone,rajalokan/keystone,mahak/keystone