Force downgrade Docker engine

Author: benwebber

scripts/install-docker.sh

@@ -2,7 +2,7 @@
 set -euo pipefail
 IFS=$'\n\t'
 
-apt-get -o Dpkg::Options::="--force-confnew" install -y docker-engine="${DOCKER_VERSION}"
+apt-get -o Dpkg::Options::="--force-confnew" install --force-yes -y docker-engine="${DOCKER_VERSION}"
 
 curl -L "https://github.com/docker/compose/releases/download/${DOCKER_COMPOSE_VERSION}/docker-compose-$(uname -s)-$(uname -m)" > /usr/local/bin/docker-compose
 chmod +x /usr/local/bin/docker-compose