Adds functionality for dual stack capabilities and automatic
population to neutron with the correct response based upon the
IP version of the provisioning/cleaning/rescue or tenant ports.
This was origianlly intended to be separated from removing the
need for [pxe]ip_version, however the resulting code changes
from doing both this and making ironic support dual stacks
touched the same tests and some of the same code, so combined
is simpler.
Change-Id: If7a296001e204ae0c9a49495731052ab33379628
cf412bc81e