git daemon: avoid calling syslog() from a signal handler

git daemon: avoid calling syslog() from a signal handler

Signal handlers should never call syslog(), as that can raise signals
of its own.

Instead, call the syslog() from the master process.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>