Test the removal of a dir which contains whiteout from lower dir,
which could crash the kernel.
The following kernel commit fixed this issue
84889d4 ovl: check dentry positiveness in ovl_cleanup_whiteouts()
Reviewed-by: Xiong Zhou <xzhou@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>
Eryu Guan