Don't pass negative token id to Lemon parser
Don't pass negative token id to Lemon parser

Newer Lemon versions throw an assertion if they encounter invalid
token ids.

Fixes LUCY-327. Thanks to Petr Pisar for the report.

nwellnhof/lucy,nwellnhof/lucy,apache/lucy,apache/lucy,apache/lucy,nwellnhof/lucy,apache/lucy,nwellnhof/lucy,apache/lucy,nwellnhof/lucy,apache/lucy,nwellnhof/lucy,apache/lucy,nwellnhof/lucy