package/irqbalance: fix sysv startup script (add mkdir /run/irqbalance)

- add mkdir -p /run/irqbalance to sysv startup script needed to
  create socket /run/irqbalance/irqbalance<pid>.sock

Fixes:

  - Bug 13541 [1]

  daemon.warn /usr/sbin/irqbalance: Daemon couldn't be bound to the file-based socket.

[1] https://bugs.busybox.net/show_bug.cgi?id=13541

Reported-by: Alfredo Pons Menargues <alfredo.pons@gmail.com>
Signed-off-by: Peter Seiderer <ps.report@gmx.net>
[yann.morin.1998@free.fr: only create in start case]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit 4a95f38f30)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/irqbalance/S13irqbalance

@@ -10,6 +10,8 @@ PID="/var/run/irqbalance.pid"
 case "$1" in
     start)
 	printf "Starting irqbalance: "
+	# for irqbalance socket /run/irqbalance/irqbalance<pid>.sock
+	mkdir -p /run/irqbalance
 	start-stop-daemon -S -q -x $EXEC -- $ARGS
 	if [ $? != 0 ]; then
 	    echo "FAILED"