cmd/dist: fix build again
cmd/dist: fix build again

I am really bad at this. Didn't hg add this file.

TBR=bradfitz
CC=golang-dev
https://codereview.appspot.com/12372043

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