xrandr.lua: Switch from awful.util.spawn to awful.spawn

It's been almost four years since this code was moved around.

Signed-off-by: Uli Schlachter <psychon@znc.in>

recipes/xrandr.lua

@@ -1,7 +1,7 @@
 --- Separating Multiple Monitor functions as a separeted module (taken from awesome wiki)
 
 local gtable  = require("gears.table")
-local awful     = require("awful")
+local spawn   = require("awful.spawn")
 local naughty = require("naughty")
 
 -- A path to a fancy icon
@@ -96,7 +96,7 @@ local function naughty_destroy_callback(reason)
      reason == naughty.notificationClosedReason.dismissedByUser then
     local action = state.index and state.menu[state.index - 1][2]
     if action then
-      awful.util.spawn(action, false)
+      spawn(action, false)
       state.index = nil
     end
   end