Ensure compatibility with Docker install.sh

[DieterReuter]

Right now it's not possible to install the official Docker .deb package for ARMHF with the recommend way. The reason behind is that the Docker install.sh depends on the lsb_release command, which is currently not available in HypriotOS.

Fix: Installing the Debian package lsb-release should fix this issue.

[DieterReuter]

Just tested it with HypriotOS 0.8.3. As soon as the lsb-release package is installed the install.sh is able to correctly detect the OS as raspbian/jessie and the installation procedure for the Docker Engine package docker-engine runs successfully.

Upgrade procedure for all HypriotOS versions to install docker-engine:

sudo apt-get update
docker rmi -f $(docker images -q)
sudo rm -f /etc/systemd/system/docker.service
sudo apt-get purge -y docker-hypriot
sudo apt-get install -y lsb-release
curl -sSL https://test.docker.com | sh
sudo apt-get clean

With HypriotOS v0.8.4 and later lsb-release package is already installed and upgrading to docker-engine will need even lesser steps:

docker rmi -f $(docker images -q)
sudo rm -f /etc/systemd/system/docker.service
sudo apt-get purge -y docker-hypriot
curl -sSL https://test.docker.com | sh
sudo apt-get clean