It is cleaner to set lease key to zero in the places where leases are not
supported (smb1 can not return lease keys so the field was uninitialized).

Addresses-Coverity: 1513994 ("Uninitialized scalar variable")
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>