Fix resource mapping for Docker
Fix resource mapping for Docker

resource_mapping() always returns all existing resource names and
their classes. available_resource_mapping() takes the dependencies
into account and only returns the ones whose dependencies have been
met.

Co-Authored-By: Richard Lee <c78a6a0a910dbb49f00feb19ae0b326dc5a3a0e9@gmail.com>
Partial-Bug: #1271226
Change-Id: I3d785d92f1d30a3caf4cb0f7721c66c9dda294c3

takeshineshiro/heat,cryptickp/heat,dims/heat,pratikmallya/heat,redhat-openstack/heat,pshchelo/heat,cwolferh/heat-scratch,dims/heat,steveb/heat,takeshineshiro/heat,jasondunsmore/heat,dragorosson/heat,pratikmallya/heat,cryptickp/heat,gonzolino/heat,NeCTAR-RC/heat,srznew/heat,srznew/heat,rdo-management/heat,rh-s/heat,maestro-hybrid-cloud/heat,steveb/heat,rdo-management/heat,jasondunsmore/heat,noironetworks/heat,rh-s/heat,miguelgrinberg/heat,cwolferh/heat-scratch,redhat-openstack/heat,maestro-hybrid-cloud/heat,pshchelo/heat,miguelgrinberg/heat,dragorosson/heat,noironetworks/heat,gonzolino/heat,openstack/heat,openstack/heat,NeCTAR-RC/heat