Update the minikube notes in DEV-GUIDE.md. (#3893)
Update the minikube notes in DEV-GUIDE.md. (#3893)

* Update the minikube notes in DEV-GUIDE.md.

I actually find I couldn't start the minikube cluster with kubeadm
when using the extra-config option.

* Update as comments

* Resolve comments

smawson/istio,frankbu/istio,geeknoid/istio,smawson/istio,frankbu/istio,geeknoid/istio,frankbu/istio,smawson/istio,smawson/istio,geeknoid/istio,istio/istio,geeknoid/istio,istio/istio,geeknoid/istio,istio/istio,istio/istio,istio/istio,smawson/istio,geeknoid/istio,frankbu/istio,frankbu/istio,smawson/istio,frankbu/istio