ksmbd: avoid to send duplicate lease break notifications

This patch fixes generic/011 when enable smb2 leases.

if ksmbd sends multiple notifications for a file, cifs increments
the reference count of the file but it does not decrement the count by
the failure of queue_work.
So even if the file is closed, cifs does not send a SMB2_CLOSE request.

Cc: stable@vger.kernel.org
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>