fail on forced shutdown of linkerd
fail on forced shutdown of linkerd

/admin/shutdown should be sufficient to kill linkerd, if it isn't, we
should fail ci

fixes #135

BuoyantIO/linkerd-examples,linkerd/linkerd-examples,BuoyantIO/linkerd-examples,linkerd/linkerd-examples,BuoyantIO/linkerd-examples,linkerd/linkerd-examples,BuoyantIO/linkerd-examples,linkerd/linkerd-examples