LP#1370630: don't log mod_deflate actions by default

This patch comments out logging of mod_deflate actions,
as this is needed only for debugging.  Otherwise,
deflate_log will grow without bound, as it isn't dealt
with by typical default logrotate configs.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
Signed-off-by: Ben Shum <bshum@biblio.org>