Debug env for tox

Running a test with pdb was difficult because testr captures
output and causes pdb prompt to quit.

Tips for how to run testr with debug are provided here:
  https://wiki.openstack.org/wiki/Testr#Debugging_.28pdb.29_Tests

This change puts these commands into a debug env in tox.ini so
you can do a command like

 tox -e debug test_auth_token_middleware

or, for more granularity:
 tox -e debug keystone.tests.test_sql_migrate_extensions.EndpointFilterExtension
 tox -e debug keystone.tests.test_sql_migrate_extensions.EndpointFilterExtension.test_downgrade

and when it hits your breakpoint you'll get the debug prompt.

This same change was made to keystone in commit c8302509 .

Change-Id: I2b5dc81f4652dc89ecbcc7c785245a81cf77a1ca
Verify token binding in auth_token middleware

The server side has had token bind checking implemented for a while. Now
that it is possible to generate bound tokens auth_token middleware
should be capable of verifying them.

Change-Id: I4f9c5855ab3102333b0738864c506e2501bf9c7e
Updated from global requirements

Change-Id: Ia662a33f3615611c380ff5862f74f18ea459bf8e
Make assertQueryStringIs usage simpler

As requested in https://review.openstack.org/#/c/65728/, this "fixes"
assertQueryStringIs so it takes a query string, rather than a dict
of lists, which is a less convenient format in many tests.

Change-Id: Ib4c49ba71f7e12bb5bcb4dfde77974f3418c7854
Merge "Debug env for tox"
Merge "Updated from global requirements"
Merge "Verify token binding in auth_token middleware"
Merge "Make assertQueryStringIs usage simpler"