Update install script

Update a few things in the install script:
1. Don't use sudo inside the script, leave it to caller to execute with sudo
2. Create a systemd file for the service

Will now log to /var/log/syslog like other systemd services.  Use
journalctl to filter on cinder-docker-driver

install.sh

@@ -12,10 +12,27 @@ DRIVER_URL="https://github.com/j-griffith/cinder-docker-driver/releases/download
 BIN_DIR="/usr/bin"
 
 do_install() {
-sudo mkdir -p /var/lib/cinder/dockerdriver
-sudo mkdir -p /var/lib/cinder/mount
-sudo curl -sSL -o $BIN_DIR/$BIN_NAME $DRIVER_URL
-sudo chmod +x $BIN_DIR/$BIN_NAME
+mkdir -p /var/lib/cinder/dockerdriver
+mkdir -p /var/lib/cinder/mount
+rm $BIN_DIR/$BIN_NAME
+curl -sSL -o $BIN_DIR/$BIN_NAME $DRIVER_URL
+chmod +x $BIN_DIR/$BIN_NAME
+echo "
+[Unit]
+Description=\"Cinder Docker Plugin daemon\"
+Before=docker.service
+Requires=cinder-docker-driver.service
+
+[Service]
+TimeoutStartSec=0
+ExecStart=/usr/bin/cinder-docker-driver &
+
+[Install]
+WantedBy=docker.service" >/etc/systemd/system/cinder-docker-driver.service
+
+chmod 644 /etc/systemd/system/cinder-docker-driver.service
+systemctl daemon-reload
+systemctl enable cinder-docker-driver
 }
 
 do_install