Remove unused domain config method paramters
Remove unused domain config method paramters

The method for getting the fully substituted config
had the optional group and option paramaters, similar to
the regular get_config() method. These paramaters are never
used outside of its class - and will complicate follow on
patches to add caching, so they are removed. These paramaters
are maintined for use by the internal methods only.

Partially Implements: blueprint domain-config-ext
Change-Id: Iaf473f0dc4e3121b2fb0f6b1c69ab2088b728881

cernops/keystone,mahak/keystone,vivekdhayaal/keystone,rajalokan/keystone,himanshu-setia/keystone,ilay09/keystone,mahak/keystone,openstack/keystone,dstanek/keystone,ajayaa/keystone,jonnary/keystone,nuxeh/keystone,cernops/keystone,jonnary/keystone,takeshineshiro/keystone,dims/keystone,takeshineshiro/keystone,openstack/keystone,roopali8/keystone,himanshu-setia/keystone,jamielennox/keystone,jumpstarter-io/keystone,mahak/keystone,ilay09/keystone,idjaw/keystone,maestro-hybrid-cloud/keystone,rajalokan/keystone,idjaw/keystone,jumpstarter-io/keystone,jumpstarter-io/keystone,nuxeh/keystone,rajalokan/keystone,ajayaa/keystone,vivekdhayaal/keystone,dstanek/keystone,jamielennox/keystone,dstanek/keystone,vivekdhayaal/keystone,maestro-hybrid-cloud/keystone,dims/keystone,nuxeh/keystone,ilay09/keystone,roopali8/keystone,klmitch/keystone,openstack/keystone,klmitch/keystone