go.tools/gotype: fix build
go.tools/gotype: fix build

R=adonovan
CC=golang-dev
https://codereview.appspot.com/11542045

tmc/mirror-go.tools,tmc/mirror-go.tools,t-yuki/go.tools.old,t-yuki/go.tools.old,tmc/mirror-go.tools,t-yuki/go.tools.old