Calgary Herald: Wednesday’s ruling by a federal court about the Kearl Lake expansion by Imperial Oil over environmental concerns should be viewed as the proverbial canary in the coal mine. A year ago, this ruling might not have been handed down. But today things are different. What’s changed is the legislation south of the border, beginning with what’s been going on in California — all of it aimed at Canada’s "dirty oil" — and ending with the hastily passed federal …