goprotobuf: update due to name change of reflect.ArrayCopy (now reflect.Copy)
goprotobuf: update due to name change of reflect.ArrayCopy (now reflect.Copy)

R=nigeltao, dsymonds
CC=golang-dev
http://codereview.appspot.com/3666041

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