Revert "Support service user and project in non-default domain"

This case can be handled by default/design by using a v3 authentication
plugin. The values also don't make sense for v2 authentication.

Having them here means extra values to support in the default case.

There has not been a release with this patch.

This reverts commit bb00caf15be9336663521a913984795af9bed185.
Related-bug: #1372142

Change-Id: I690f39284010906a0171178511729749ccc566b8
Merge "Revert "Support service user and project in non-default domain""