[PATCH @ ] Fix for FETCH/NEXTKEY problem in all *DB*_File modules

This is a patch for the bug that Robin Barker reported a while back where
the use of "each" with a tied hash that used a dbm filter could do the wrong
thing.

For all but GDBM_File & ODBM_File this just involved getting the modules to
ignore the input key. For [GO]DBM_File, I've got them to work with a copy of
the key in FETCH.

Paul

• [PATCH @ ] Fix for FETCH/NEXTKEY problem in all *DB*_File modules by Paul Marquess