start: kill nm-applet on start

It's not unusual for it to become out-of-sync. Dunno if it is because of
configuration change or anything else, but an easy solution is to
restart it often.

rc/start.lua

@@ -3,6 +3,8 @@ awful.util.spawn("compton --backend glx --xrender-sync --xrender-sync-fence --vs
 
 -- Start idempotent commands
 local execute = {
+   -- Kill any running nm-applet
+   "pkill nm-applet",
    -- Start PulseAudio
    "pulseaudio --check || pulseaudio -D",
    "xset -b",	-- Disable bell