Remove some extra cleanup umounts

Leftovers from when we used to bind-mount PKGDEST and SRCDEST

Signed-off-by: Aaron Griffin <aaronmgriffin@gmail.com>

makechrootpkg

@@ -111,8 +111,6 @@ fi
 cleanup ()
 {
     echo "cleaning up unioned mounts"
-    umount "$chrootdir/union/pkgdest" 2>/dev/null
-    umount "$chrootdir/union/srcdest" 2>/dev/null
     umount "$chrootdir/union"
 }