ovl: fix getcwd() failure after unsuccessful rmdir

ovl: fix getcwd() failure after unsuccessful rmdir

Orabug: 23330998

[ Upstream commit ce9113bbcbf45a57c082d6603b9a9f342be3ef74 ]

ovl_remove_upper() should do d_drop() only after it successfully
removes the dir, otherwise a subsequent getcwd() system call will
fail, breaking userspace programs.

This is to fix: https://bugzilla.kernel.org/show_bug.cgi?id=110491

Signed-off-by: Rui Wang <rui.y.wang@intel.com>
Reviewed-by: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Cc: <stable@vger.kernel.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
(cherry picked from commit e786702fff38e2b5142029d6de615abf1c8e436f)

Signed-off-by: Dan Duval <dan.duval@oracle.com>