Change from "cert-only" in RFC2633-bis-01

Blake,

I think that there may be a major problem in making this change.

Issues: 
1.  You need to have a backwards compability section describing what the
old "certs-only" smime-type is and what it does.
2.  I dislike the term cert-management, because you are not doing
certificate managmement.  A better term would be cert-distribution.

Personally I have no problem with leaving this smime-type as is.

Jim