netatalk: ad missing event_del() for SIGHUP

This was missing in commit 47de27c3b1bec126c2343709a884f9882fab97a6,
fix for bug #579.

Signed-off-by: Ralph Boehme <rb@sernet.de>
dbd: add missing return value

Signed-off-by: Ralph Boehme <rb@sernet.de>