CONTRIBUTORS: add Raul Silvera (Google CLA)
CONTRIBUTORS: add Raul Silvera (Google CLA)

Raul wrote the pprof code in CL 153750043.

LGTM=bradfitz, r
R=r, bradfitz
CC=golang-codereviews
https://codereview.appspot.com/146450043

wesolows/golang,wesolows/golang,firebitsbr/golang-old,wesolows/golang-old,wesolows/golang-old,wesolows/golang,firebitsbr/golang-old,firebitsbr/golang-old,wesolows/golang,firebitsbr/golang-old,wesolows/golang-old,firebitsbr/golang-old,wesolows/golang,wesolows/golang-old,wesolows/golang-old,firebitsbr/golang-old,wesolows/golang-old,wesolows/golang-old,wesolows/golang,firebitsbr/golang-old,wesolows/golang,firebitsbr/golang-old