r26298: Use metze's schema loading code to pre-initialise the schema into the

r26298: Use metze's schema loading code to pre-initialise the schema into the

samdb before we start writing entries into it.

In doing so, I realised we still used 'dnsDomain', which is not part
of the standard schema (now removed).

We also set the 'wrong' side of the linked attributes for the
masteredBy on each partition - this is now set in provision_self_join
and backlinks via the linked attributes code.

When we have the schema loaded, we must also have a valid domain SID
loaded, so that the objectclass module works.  This required some ejs
glue.

Andrew Bartlett