net/http: fix race in sendfile test
net/http: fix race in sendfile test

Whoops. Consume the body of the first request
before making the subsequent /quit request.

R=golang-dev, untheoretic
CC=golang-dev
http://codereview.appspot.com/5674054

h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang