Cleanup superfluous string comprehension and coersion

Remove the superfluous string comprehension and coersion to string
type in a join within the keystone.notifications module. The elements
in the namedtuple are already string types.

Change-Id: I107102fabc2f6671e10bcf1b5db40529fdb19d69
Test cleanup: do not leak FDs during test runs

Avoid leaking file descriptors during test runs. Instead use a secure
tempfile fixture that guarantees the file descriptor from
tempfile.mkstemp is closed and that performs the appropriate cleanup
on the tempfile name in the cleanup phase.

Change-Id: I7e1ddd3122d72d8850794df9467f7b6c0608ac2d
Lower log level for notification registration

Registering an internal notification isn't something that an admin
would generally be interested in, and if they are they can configure
debug logging for keystone.notifications.

Closes-Bug: #1363704

Change-Id: Id7cd3bf2e1f373b818329978553eb53af399386c
Mark the revoke kvs backend deprecated, for removal in Kilo

Although the kvs.Base was marked as deprecated, the individual
backends were not.  This marks the kvs revoke backend.

Change-Id: I6592cce10687e355536a4c9f89fc885692a73e23
Partially-implements: bp deprecated-as-of-juno
Implement validation on Trust V3 API

Use JSONschema on create operations on V3 Trust API.

This change refactors a lot of the test_v3_auth tests to get them to
pass with proper validation.

Closes-Bug: #1362344
bp: api-validation

Change-Id: If4b59a6ac84e308eff8bf5ea35772173b0ba7fe5
Implementation of Endpoint Grouping

The Endpoint Filter extension has been extended to support Endpoint
Grouping which provides a dynamic endpoint attribute filtering capability
that is directly associated with a project.

Change-Id: I7b628ac565f58077ff7521458cc1d02b3bf47d29
implements bp multi-attribute-endpoint-grouping
Adds region back into the catalog endpoint

This was removed as a side effect of this commit:
8ea1b14e4d7cf6d67f9796e1b3d13f4cc198015b

Change-Id: I495589e850cf110ff264ec800638c6673e6a98e0
Closes-Bug: #1364463
Merge "Mark the revoke kvs backend deprecated, for removal in Kilo"
Merge "Implement validation on Trust V3 API"
Merge "Implementation of Endpoint Grouping"
Merge "Adds region back into the catalog endpoint"
Merge "Test cleanup: do not leak FDs during test runs"
Merge "Cleanup superfluous string comprehension and coersion"
Merge "Lower log level for notification registration"