In 'clean' command, -y option was used to keep only the year in the
date tag (YYYY-MM-DD was changed into YYYY).

This option could be useful when the CDs were ripped by sound-juicer
for example, in particular when the date was YYYY-01-01 (which meant
that the exact date was unknown).

Now I use mycdrip (based on cdparanoia) to rip the CDs, and the date is
set manually with 'seta' command. So I don't need this option anymore.

Signed-off-by: Cédric Marie <cedric@hjuvi.lautre.net>