r20149: Remove the smb.conf distinction between PDC and BDC. Now the correct

r20149: Remove the smb.conf distinction between PDC and BDC.  Now the correct
way to setup a Samba4 DC is to set 'server role = domain controller'.

We use the fSMORoleOwner attribute in the base DN to determine the PDC.

This patch is quite large, as I have corrected a number of places that
assumed taht we are always the PDC, or that used the smb.conf
lp_server_role() to determine that.

Also included is a warning fix in the SAMR code, where the IDL has
seperated a couple of types for group display enumeration.

We also now use the ldb database to determine if we should run the
global catalog service.

In the near future, I will complete the DRSUAPI
DsGetDomainControllerInfo server-side on the same basis.

Andrew Bartlett
(This used to be commit 67d8365e831adf3eaecd8b34dcc481fc82565893)