Fix disk detection

Nodes with multiple devices need a random disk identifier written
on the disk so that the BIOS can detect boot order properly.
fdisk does that. parted nukes the identifer. In addition the
parted code only handled /dev/sd? devices, not /dev/cciss or
/dev/hdX or whatever else we support right now.
Fix syntax errors in tftp xinetd file

This causes xinetd fail to start the tftp service.
Also switch the order of service definition vs usage, this
seems to be relevant with Chef 10.
Merge pull request #186 from dirkmueller/fix_disk_detection

Fix disk detection
Merge pull request #188 from dirkmueller/fix_tftp_boot

Fix tftp boot
Quick hack to try and nuke the vgs as part of wiping the drives.
Merge pull request #191 from VictorLowther/pull-req-release-pebbles-master-7c5257af784759eacfafa5f491c17946de7b8420

+2 Zap volume groups properly at hard drive wiping time. [1/1]
fix syntax error