[Remi]

I solved this by adding "$local_fs $network" to the pilight init script
Now no manual restart is needed after a reboot.

nano /etc/init.d/pilight

#! /bin/sh
### BEGIN INIT INFO
# Provides: pilight-daemon
# Required-Start: $local_fs $network $remote_fs $syslog
# Required-Stop: $remote_fs $syslog

After editing run:
update-rc.d pilight defaults