Cleanup overlay script

- Create the upper and work dirs if they don't exist yet.
 - If the target doesn't exist, let it fail. The configuration
   is bonkers.

Signed-off-by: David Oberhollenzer <goliath@infraroot.at>

scripts/overlay.sh

@@ -5,17 +5,7 @@ upper=/cfg/overlay/${1}
 work=/cfg/overlay/${1}_work
 target=${2}
 
-if [ ! -d "$target" ]; then
-	exit
-fi
-
-if [ -d "$lower" ]; then
-	if [ -d "$upper" ]; then
-		mkdir -p "$work"
+mkdir -p "$work" "$upper"
 mount -t overlay overlay \
       -olowerdir=${lower},upperdir=${upper},workdir=${work} \
-			${target}
-	else
-		mount --bind "$lower" "$target"
-	fi
-fi
+      "$target"