r15942: Remove the sync internal ldb calls altogether.

r15942: Remove the sync internal ldb calls altogether.
This means that some modules have been disabled as well as they
have not been ported to the async interface

One of them is the ugly objectclass module.
I hope that the change in samldb module will make the MMC happy
without the need of this crappy module, we need proper handling
in a decent schema module.

proxy and ldb_map have also been disabled
ldb_sqlite3 need to be ported as well (currenlty just broken).
(This used to be commit 51083de795bdcbf649de926e86969adc20239b6d)