added samr_set_domain_info and samr_unknown_2E.

added samr_set_domain_info and samr_unknown_2E.
We now get the full account policy window in usermanager, and the
framework to store all those values. I plan to add a TDB file to store
them.

oh, and found that the last value in a sam_unknown_info_12_inf struct is
an uint16 and not a uint32.

andrewb: you hardcoded the MAX_PASSWORD_AGE to 21 days. We can now turn it
to a value setable in usermanager.

        J.F.