Fix the tracking of 'left' and 'right' indices in chunk_file.
Fix the tracking of 'left' and 'right' indices in chunk_file.

paulproteus/livegrep,paulproteus/livegrep,wfxiang08/livegrep,wfxiang08/livegrep,lekkas/livegrep,lekkas/livegrep,paulproteus/livegrep,wfxiang08/livegrep,lekkas/livegrep,paulproteus/livegrep,lekkas/livegrep,wfxiang08/livegrep,lekkas/livegrep,wfxiang08/livegrep,paulproteus/livegrep,paulproteus/livegrep,lekkas/livegrep,wfxiang08/livegrep