nix/pkgs/openwrt/usteer-stats: fix fifo path to writable location

nix/pkgs/openwrt/usteer-info.sh

@@ -1,3 +1,3 @@
 #! /bin/sh
-[ -p /var/run/usteer-info ] || exit 0
-exec /bin/ubus call usteer local_info > /var/run/usteer-info
+[ -p /tmp/usteer-info ] || exit 0
+exec /bin/ubus call usteer local_info > /tmp/usteer-info

nix/pkgs/openwrt/usteer-stats.sh

@@ -3,10 +3,10 @@
 HOSTNAME=`cat /proc/sys/kernel/hostname`
 INTERVAL=60
 
-[ -p /var/run/usteer-info ] || mkfifo /var/run/usteer-info
+[ -p /tmp/usteer-info ] || mkfifo /tmp/usteer-info
 
 while true; do
-    DATA="$(cat /var/run/usteer-info)"
+    DATA="$(cat /tmp/usteer-info)"
     cd /sys/class/net
     for iface in wlan*; do
         eval $( echo "$DATA" | jsonfilter  \