Automatic merge from submit-queue

Replace with explicit kubernetes fork path

At other place in development.md, explicit kubernetes fork path has been existed:

    mkdir -p $GOPATH/src/k8s.io
    cd $GOPATH/src/k8s.io
    # Replace "$YOUR_GITHUB_USERNAME" below with your github username
    git clone https://github.com/$YOUR_GITHUB_USERNAME/kubernetes.git

the following is easy to be confused and can be replaced with same description:

    git clone https://path/to/your/fork .