[qmp-system] Fix wget() in bmx6json.lua from luci-app-bmx6

Dirty fix for #446 while it is not fixed upstream (see
https://github.com/openwrt-routing/packages/issues/436

)
Signed-off-by: Roger Pueyo Centelles <roger.pueyo@guifi.net>

packages/qmp-system/files/etc/uci-defaults/qmp_fix_luci_app_bmx6_wget_race_condition

+#!/bin/sh
+
+# Update BMX6's bmx6json.lua file to avoid race condition described in
+# https://github.com/openwrt-routing/packages/issues/436
+# TODO: Remove this script once the bug has been fixed upstream
+FILENAME="/usr/lib/lua/luci/model/bmx6json.lua"
+if [ -f $FILENAME ]; then
+        sed -i 's|raw,err = wget(url..field,1000)|raw,err = wget(url..field,1000)\n\t\tsys.exec("")|g' $FILENAME
+fi
+
+exit 0