provision: Use names.domainsid and names.domainguid

provision: Use names.domainsid and names.domainguid

This is better than passing around parameters to functions all over
the provision stack and makes it easier to pass in a seperate forest
SID when we start to support subdomains.

Change-Id: I3787f4f3433ca04628f888135c7c0c8195379542
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Pair-programmed-with: Garming Sam <garming@catalyst.net.nz>
Signed-off-by: Garming Sam <garming@catalyst.net.nz>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Reviewed-By: Jelmer Vernooij <jelmer@samba.org>