Bug 2399: All status fields in the item edit interface offer two blank/null entries...

Bug 2399: All status fields in the item edit interface offer two blank/null entries per dropdown instead of one

Removes the '0' values without description from the sample date for
authorised values.

To test:
1) Verify that SQL files load correctly
- truncate authorised_values; /* empty authorised values table */
- load sample data using one of the SQL files
2) Check cataloging interface - all status fields should only show 1 empty line

Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>