clean up old pairwise dep tree code.
clean up old pairwise dep tree code.

Impactstory/depsy,total-impact/depsy,total-impact/depsy,total-impact/depsy,total-impact/software,total-impact/software,total-impact/software,total-impact/software,total-impact/depsy,Impactstory/depsy,Impactstory/depsy,Impactstory/depsy