DKIM and DomainKey signatures

[Bron Gondwana]

Hi all,

Any objection to adding this?

+    /* signatures tend to be large, and are useless without the body */
+    { "dkim-signature", BIT32_MAX },
+    { "domainkey-signature", BIT32_MAX },
+

Those headers take up a reasonable amount of space in cyrus.cache,
and I can't see that any client would want them without asking for
the body, since they're only useful if you can actually check
them!

Bron.