Disable automatic 'ATA over Ethernet discovery'

Disable automatic 'ATA over Ethernet discovery'

/usr/lib/modules-load.d/aoetools.conf by default contains:

| ## If you need to restrict the interfaces aoe will use, copy this
| ## file to /etc/modules-load.d/ and use this example:
| # aoe aoe_iflist="eth0,eth1"
|
| ## Load aoe driver with no interface restriction:
| aoe

and /lib/systemd/system/aoe-discover.service contains:

| [Unit]
| Description=ATA over Ethernet discovery
| BindsTo=sys-devices-virtual-aoe-discover.device
| DefaultDependencies=no
| Conflicts=shutdown.target
| After=network-online.target
|
| [Service]
| Type=oneshot
| ExecStart=/sbin/aoe-discover

Since the aeotools.conf file tells systemd to load the aoe module
which then triggers the udev rule we end up with automatic
aoe-discover execution on default Grml boot, even though we
disable the aoe-discover service (since enabling/disabling only
affects starting via transitive dependencies, but the udev rule
is doing the equivalent of `systemctl start $unit`). By removing
/usr/lib/modules-load.d/aoetools.conf we ensure that automatic
'ATA over Ethernet discovery' is NOT executed, though if a user
runs 'modprobe aoe' it executes aoe-discover as intended.

Thanks: Felipe Sateler + Darshaka Pathirana for help in coming up with a solution
Closes grml/grml#32