Disable probing of network interfaces

provides a significant speedup on running sudo on a larger
neutron deployment.

see http://www.sudo.ws/pipermail/sudo-workers/2014-January/000835.html
crowbar_join.suse: Reset reboot flag after reboot

Currently we reset node[:crowbar_wall][:wait_for_reboot] always before a
chef-client run. That doesn't work if there's another chef-client run
before the reboot happens.
Add a check which compares the stored time when the reboot was requested
and the time the node was booted to verify that the reboot finished.
Fixed a condition where uefi is not defined
Merge pull request #325 from tboerger/feature/uefi-hotfix

Fixed a condition where uefi is not defined
Merge pull request #324 from toabctl/fix/reboot-handler-race

crowbar_join.suse: Use file as reboot indicator
Merge pull request #319 from dirkmueller/master

Disable probing of network interfaces
Add support for Windows Server 2012 R2
Share Windows files among Windows version

There's no need to copy the same files in many directories.
Make it possible to use several versions of Windows at the same time

We were limited by the fact that we hardcoded the version of Windows in
tftpd.conf. Instead of doing that, we use \x in tftpd.conf which matches
the IP address of the requesting host, and with this IP address, we
create a symlink to the correct windows directory.
Fix typos in comment