libndb: remove db file size limit

libndb: remove db file size limit

Removes the 128 kB limit for files making up the database.
We used to skip over and complain about files that exceeded
the limit, forcing the user to generate hash files.

This caused things to inexplicably stop working after a file
hit the hidden limit, which is unreasonable behaviour considering
that libndb happily, albeit slowly, works with bigger files.