Add a wrapper to reconnect when SamDB LDB connection is lost

On OCS Manager.
The first argument of LdbError is an error code. If you're going to handle one kind of Ldb exception only, then please use the constant (ldb.ERR_OPERATIONS_ERROR I think) rather than hardcoding the value.

If this is the case, can you add a comment saying why you only want to handle this kind of Ldb error?