downgradedatabase: adding special case for MDB

downgradedatabase: adding special case for MDB

Though this script was initially written for undoing GUID indexing on
TDB databases, we're repurposing it to do a full downgrade of any
database. MDB databases can't be DN indexed, but they can have pack
format version 2 and ORDERED_INTEGER data types, which must be removed
during a downgrade.

Signed-off-by: Aaron Haslett <aaronhaslett@catalyst.net.nz>
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Garming Sam <garming@catalyst.net.nz>
Pair-Programmed-With: Andrew Bartlett <abartlet@samba.org>