* Use INVOCATION_ID to detect execution under systemd, since as of a9b5a193 NOTIFY_SOCKET is now cleared by the server code.
* Set the unit type to notify by default for both server and agent, which is what Rancher-managed installs have done for a while.
Signed-off-by: Brad Davidson <brad.davidson@rancher.com>
(cherry picked from commit bd5fdfce)
Signed-off-by: Brad Davidson <brad.davidson@rancher.com>