network down is not enough, clean everything to avoid issues

medard.egue

Hello,
I noticed that using "./network.sh down" to clean resources is generally not enough and will result in next command to create channels or deploy chaincode to fail.

I always run the following docker command to really clean everything:
docker stop $(docker ps -aq)
docker rm $(docker ps -aq)
docker volume prune
docker volume rm $(docker volume ls -q)

After that, all lab commands succeed.