Bug 635009 - Add one-way AD sync capability
This patch adds one-way AD sync capability. A new "oneWaySync"
configuration attribute can be added to a sync agreement to specify
which direction one-way sync should work (values of "toWindows" and
"fromWindows" will be accepted).
Internally, the server will just skip pushing/pulling updates depending
on the direction that sync is configured for. We will still update the
RUV as if entries were actually synced.
One can introduce inconsistencies by updating synced entries on the
receiving side when using one way sync. This should be avoided by
restricting update access to synced entries.