Make disaggregation information consistent in show spf output

[brunorijsman]

The output of show spf reports information about disaggregation in two places:

1. The "Destination" column may report "(Disagg)" after the prefix. This is intended to report whether the prefix was received as a regular prefix or as a positive disaggregation prefix or as a negative disaggregation prefix in the received TIE. But it does not distinguish between positive and negative disaggregation. Make this report "(Pos-Disagg)" or "(Neg-Disagg)"

2. The "Disaggregate" column is intended to report whether the current node should initiate positive or negative disaggregation for the prefix. This is exactly what it reports for positive disaggregation. But for negative disaggregation it incorrectly reports whether the prefix was received as a negative disaggregation prefix TIE and not whether it should initiate (or propagate) negative disaggregation for the prefix.

[brunorijsman]

The first item has been done