package/mender: fix sysv startup script

Mender is a service explicitly written for systemd and so it doesn't
fork on background, doesn't redirect outputs and doesn't create a pid
file by itself.
To make the service running correctly is therefore necessary to use the
-m switch of start-stop-daemon to create the pid file and -b option to
send the process to background.
Logging is preserved because the service will log anyway on syslog.

Signed-off-by: Angelo Compagnucci <angelo@amarulasolutions.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/mender/S42mender

@@ -24,7 +24,7 @@ start() {
 	printf "Starting mender service: "
 	umask 077
 
-	start-stop-daemon -S -q -p /var/run/mender.pid \
+	start-stop-daemon -S -q -b -m -p /var/run/mender.pid \
 		--exec /usr/bin/mender -- -daemon
 	[ $? = 0 ] && echo "OK" || echo "FAIL"
 }