Don't crash when dockerCli is nil
Don't crash when dockerCli is nil

paulbellamy/weave,paulbellamy/weave,weaveworks/weave,paulbellamy/weave,weaveworks/weave,paulbellamy/weave,weaveworks/weave,n054/weave,weaveworks/weave,n054/weave,n054/weave,n054/weave,n054/weave