Rev6: Separate Port Justifications

[dcmgashcisco]

Tidy based on Mohamed's comment:

That RFC says: "However, there is no IETF consensus on when separate ports should be used for secure and insecure variants of the same service [RFC2595] [RFC2817] [RFC6335]. The overall preference is for use of a single port, as noted in Section 6 of this document and Section 7.2 of [RFC6335], but the appropriate approach depends on the specific characteristics of the service."