[mif] Small nit on route option draft

[Ted Lemon <[e-mail]>]

I would like to ask that you reverse the prefix length and metric fields in the option.  The reason for this is that the prefix length and prefix look like they are going to become a common encoding (they are also used in a proposed source address configuration option). They are essentially a single value, expressed as two fields. I have asked the source address draft authors to group the prefix length and prefix together; I think it makes sense to do the same thing here.   This will speed adoption of both drafts, I think. 

In order for this to be useful, of course, it would be necessary for you to adopt the variable length format for the prefix that is used in that draft.  The draft is called draft-ietf-6man-address-select-opt-01. 

I do apologize for interjecting this so late in the process, but I think it's a substantial win to use the same format for the same data across different options.