s4:provision: don't use hardcoded values for 'nextRid' and 'rIDAvailablePool'

s4:provision: don't use hardcoded values for 'nextRid' and 'rIDAvailablePool'

On Windows dcpromo imports nextRid from the local SAM,
which means it's not hardcoded to 1000.

The initlal rIDAvailablePool starts at nextRid + 100.

I also found that the RID Set of the local dc
should be created via provision and not at runtime,
when the first rid is needed.
(Tested with dcpromo on w2k8r2, while disabling the DNS
 check box).

After provision we should have this (assuming nextRid=1000):

rIDAllocationPool: 1100-1599
rIDPrevAllocationPool: 1100-1599
rIDUsedPool: 0
rIDNextRID: 1100

rIDAvailablePool: 1600-1073741823

Because provision sets rIDNextRid=1100, the first created account
(typically DNS related accounts) will get 1101 as rid!

metze