Remove kwargs from manager calls / general cleanup

Cleaned up keystone.trust.controllers.TrustV3.delete_trust to use
the proper "delete_tokens" method from the token_api.

Added "delete_trust" reference method to keystone.trust.core.Driver.

Named-argument cleanup:

This patch removes some use of kwargs from manager calls where not
required. Dogpile.cache (the targeted caching library) does not
support kwargs out of the box with its cache-key-generator. This
change allows us to support the default cache-key-generator.

Cleanup done on a couple calls in keystone.assignment.core to remove
un-needed named-arguments.

Added a note on keystone.token.core.Driver indicating that
list_tokens should be considered a private method only used by
"delete_tokens" and if treated as such, should not need caching.

In keystone.common.controller.V3Controller._get_domain_id_for_request
fixed named-argument call to token_api.get_token

In keystone.contrib.oauth1.controllers.OAuthControllerV3.authorize
fixed named-argument call to token_api.get_token

partial-blueprint: caching-layer-for-driver-calls
Change-Id: I1fddb4e2db9a24a9ebc544aabe63a3b1fdcfc374
Merge "Remove kwargs from manager calls / general cleanup"