fix borked docker machine

fix_borked_docker_machine.sh

$ docker-machine ssh dev

Boot2Docker version 1.9.0, build master : 16e4a2a - Tue Nov  3 19:49:22 UTC 2015
Docker version 1.9.0, build 76d6bc9

$ sudo -i

$ rm -rf /var/lib/docker/network

# exit from the Docker host and then run

$ docker-machine env dev

export DOCKER_TLS_VERIFY="1"
export DOCKER_HOST="tcp://192.168.99.100:2376"
export DOCKER_CERT_PATH="/Users/mansfield/.docker/machine/machines/dev"
export DOCKER_MACHINE_NAME="dev"
# Run this command to configure your shell:
# eval "$(dm env dev)"