go.tools/cmd/oracle: output help messages to stderr for consistency Fixes golang/go#6838.
go.tools/cmd/oracle: output help messages to stderr for consistency
Fixes golang/go#6838.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/36820043

maddyonline/tools,dmitris/tools,nicot/tools,runcom/tools,nicot/tools,syreclabs/go-tools,argandas/tools,syreclabs/go-tools,syreclabs/go-tools,dmitris/tools,runcom/tools,4ad/tools,4ad/tools,dmitris/tools,josharian/tools,matryer/tools,springning/tools,maddyonline/tools,syreclabs/go-tools,argandas/tools,golang/tools,magiccao/tools,jdhenke/tools,sshetty10/tools,cmars/tools,springning/tools,cmars/tools,springning/tools,syreclabs/go-tools,josharian/tools,nicot/tools,magiccao/tools,golang/tools,springning/tools,matryer/tools,cw2018/tools,golang/tools,maddyonline/tools,cw2018/tools,sshetty10/tools,jdhenke/tools,argandas/tools,glasser/golang-tools,maddyonline/tools,matryer/tools,syreclabs/go-tools,josharian/tools,cw2018/tools,sshetty10/tools,argandas/tools,nicot/tools,golang/tools,cmars/tools,matryer/tools,4ad/tools,jdhenke/tools,josharian/tools,cw2018/tools,runcom/tools,glasser/golang-tools,dmitris/tools,golang/tools,sshetty10/tools,jdhenke/tools,magiccao/tools,glasser/golang-tools,cmars/tools,runcom/tools,glasser/golang-tools,magiccao/tools