rafthttp: log stream stopped message before closing channel
rafthttp: log stream stopped message before closing channel

Was causing spurious goroutine leak failures in testing.

yudai/etcd,ravigadde/etcd,xiang90/etcd,nekto0n/etcd,dannysauer/etcd,OyTao/etcd_learning,bluebreezecf/etcd,ajityagaty/etcd,lorneli/etcd,a-robinson/etcd,endocode/etcd,YuleiXiao/etcd,rnaveiras/etcd,tguangch/etcd,insequent/etcd,sinsharat/etcd,akauppi/etcd,armstrongli/etcd,zaphod-concur/etcd,armstrongli/etcd,lumjjb/etcd,mqliang/etcd,endocode/etcd,bdarnell/etcd,plasticbox/etcd,bdarnell/etcd,mkumatag/etcd,akauppi/etcd,fanminshi/etcd,qqsun8819/etcd,etcd-io/etcd,handsomesun/etcd,tguangch/etcd,li-ang/etcd,hongchaodeng/etcd,ajityagaty/etcd,coreos/etcd,lumjjb/etcd,yudai/etcd,CrazyJvm/etcd,heyitsanthony/etcd,mickep76/etcd,gyuho/etcd,luxas/etcd,sebrandon1/etcd,a-robinson/etcd,sebrandon1/etcd,whuwxl/etcd,CrazyJvm/etcd,lorneli/etcd,mkumatag/etcd,etcd-io/etcd,joshix/etcd,mqliang/etcd,luxas/etcd,sinsharat/etcd,insequent/etcd,bluebreezecf/etcd,mkumatag/etcd,gyuho/etcd,ravigadde/etcd,zaphod-concur/etcd,mickep76/etcd,glevand/coreos--etcd,hongchaodeng/etcd,fanminshi/etcd,jlamillan/etcd,visheshnp/etcd,qqsun8819/etcd,OyTao/etcd_learning,plasticbox/etcd,visheshnp/etcd,rnaveiras/etcd,joshix/etcd,heyitsanthony/etcd,rchicoli/etcd,coreos/etcd,whuwxl/etcd,vimalk78/etcd,mqliang/etcd,li-ang/etcd,jlamillan/etcd,handsomesun/etcd,xiang90/etcd,etcd-io/etcd,nekto0n/etcd,rchicoli/etcd,dannysauer/etcd,cockroachdb/etcd,rnaveiras/etcd,vimalk78/etcd,ajityagaty/etcd,glevand/coreos--etcd,YuleiXiao/etcd,cockroachdb/etcd