UPSTREAM: fs/smb/client: Reset password pointer to NULL

commit e6e43b8a upstream.

Forget to reset ctx->password to NULL will lead to bug like double free

Bug: 303146572
Cc: stable@vger.kernel.org
Cc: Willy Tarreau <w@1wt.eu>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Quang Le <quanglex97@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit f555a508)
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: Iec1eb857124e3b6ffa6dbbeb5f796087a6194057