goprotobuf: gofix for package rename
goprotobuf: gofix for package rename

R=golang-dev, dsymonds
CC=golang-dev
http://codereview.appspot.com/5343051

ruiaylin/goprotobuf,wfxiang08/goprotobuf,t3rm1n4l/goprotobuf,tonnerre/go-protobuf,liumuqi/goprotobuf,polydawn-ports/goprotobuf,adwinsky/goprotobuf,supiyun/goprotobuf