Clean up service file

There is some extra magic that doesn't look like it's needed: The
actual service is a oneshot, and it used during startup only.

debian/aoetools.aoe-discover.service

@@ -2,8 +2,6 @@
 Description=ATA over Ethernet discovery
 Documentation=man:aoe-discover(8)
 BindsTo=sys-devices-virtual-aoe-discover.device
-DefaultDependencies=no
-Conflicts=shutdown.target
 After=network-online.target
 
 [Service]