when removing node, remove configs for all his dhcp hosts
(not just ones matching currently known MACs)
move dir path to attributes, in case of later(or platform) changes
ensure correct path
Pessimize usb devices when determining boot device

Otherwise it believes that this machine is booted via floppy:

pci-0000:00:1a.0-usb-0:1.4:1.0-scsi-0:0:0:0 -> ../../sr0
pci-0000:00:1a.0-usb-0:1.4:1.0-scsi-0:0:0:1 -> ../../sde
pci-0000:00:1a.0-usb-0:1.4:1.0-scsi-0:0:0:2 -> ../../sdf
pci-0000:00:1f.2-scsi-1:0:0:0 -> ../../sda
pci-0000:00:1f.2-scsi-2:0:0:0 -> ../../sdb
pci-0000:00:1f.2-scsi-3:0:0:0 -> ../../sdc
pci-0000:00:1f.2-scsi-4:0:0:0 -> ../../sdd

Change it into a two pass approach, first ignoring usb, then going over
all devices.
Merge pull request #245 from dirkmueller/release/roxy/master

Pessimize usb devices when determining boot device
Merge pull request #225 from jsuchome/release/roxy/master

when removing node, remove configs for all his dhcp hosts
Remove unused variable assignments
Merge pull request #246 from vuntz/cleanup

Remove unused variable assignments