xlock: lock screen faster by invoking i3lock directly

Instead of trying to mess with xautolock to trigger locking, just
invoke i3lock directly.

bin/locker

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+exec i3lock -n -i $HOME/.cache/awesome/current-wallpaper.png

bin/xautolock

@@ -2,9 +2,10 @@
 
 icon="$1"
 notify=$(dirname $(readlink -f "$0"))/notify-lock
+locker=$(dirname $(readlink -f "$0"))/locker
 
 exec xautolock \
     -time 4 \
-    -locker "i3lock -n -i $HOME/.cache/awesome/current-wallpaper.png" \
+    -locker "$locker" \
     -notify 10 \
     -notifier "$notify $icon"

rc/xlock.lua

@@ -11,7 +11,8 @@ config.keys.global = awful.util.table.join(
    config.keys.global,
    awful.key({}, "XF86ScreenSaver",
              function()
-                awful.util.spawn_with_shell("xautolock -locknow & sleep 1 ; xautolock -enable ; sleep 1 ; xautolock -locknow", false)
+                awful.util.spawn(awful.util.getdir("config") ..
+                                 "/bin/locker", false)
              end))
 
 -- Configure DPMS