This reclassifies dragon scale mail as magic and leaves dragon
scales as non-magic. Changing the latter would make it be easier
to obtain magic armor via polymorph; just kill some dragons and toss
their scales on the pile. Unfortunately the logic used suggests that
unicorn horns ought to be non-magic too, but I left them as magic.
(Making them become non-magic would actually be a good idea as far
as balancing polypiling goes, but it's awfully hard to justify when
they produce should a wide-ranging magical effect when applied.)