Fixed addon config parsing

The check for a comment line wasn't actually working
before. Shell quoting ftl.

Signed-off-by: Simo Leone <simo@archlinux.org>

hooks/archiso

@@ -66,7 +66,7 @@ run_hook ()
         msg ":: Mounting addons"
         while read img mountpoint type; do
             # check if this line is a comment (starts with #)
-            [ "${img#'#'}" != "${img}" ] && continue
+            [ "${img#"#"}" != "${img}" ] && continue
 
             if [ "${type}" = "bind" ]; then
                 _mnt_bind ${img} ${mountpoint}