ldb: Release ldb 2.0.1

ldb: Release ldb 2.0.1

* Rework pack routines to remove unused features:
  - ldb_unpack_data_only_attr_list_flags() is removed
  - LDB_UNPACK_DATA_FLAG_NO_DATA_ALLOC is now always implied

  This improves the unpack performace significantly.

* Improve search performance via new internal flag
  LDB_UNPACK_DATA_FLAG_READ_LOCKED which removes a memdup

* Improve search performance during full scan by ignoring
  index records early.

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Gary Lockyer <gary@catalyst.net.nz>