SMB3: GUIDs should be constructed as random but valid uuids

commit fa70b87cc6641978b20e12cc5d517e9ffc0086d4 upstream.

GUIDs although random, and 16 bytes, need to be generated as
proper uuids.

Signed-off-by: Steve French <steve.french@primarydata.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Reported-by: David Goebels <davidgoe@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>