go.tools/go/gcimporter: ImportData has no need for *bufio.Reader, can get just io.Reader.
go.tools/go/gcimporter: ImportData has no need for *bufio.Reader, can get just io.Reader.

R=golang-dev, gri
CC=golang-dev
https://codereview.appspot.com/31620043

Committer: Robert Griesemer <a6752097faebf1f02d80107d77a9be009089afe3@golang.org>

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