Pipeline filter is 'authtoken' and not 'tokenauth'

The pipeline fileter in the api-paste.ini for the keystone
middleware was renamed to 'authtoken'. Trove install is not
able to authenticate against keystone unless this is renamed

Change-Id: I6f912d29c143b3acbc43da222cf8b4c3fafb2c8d
Merge "Pipeline filter is 'authtoken' and not 'tokenauth'"
Merge branch 'master' of github.com:openstack-dev/devstack