Clean up dhcp_host provider a little bit
Rebooting a node should always mark the node as not alive.
Fix up provisioner-os-install role a bit.

We need to be able to talk to the webserver to see if we are ready to
install before rebooting, so we now want the provisioner-webserver
attribute.

Also, make provisioner-os-install explicitly depend on crowbar-managed-node.
Make the scriptjig runner log all the things.
Have the provisioner's update_nodes recipe confirm the node bootstate.

This gives client nodes a way to tell when the provisioner has doe all
the work needed to allow htem to boot into their next desired state.
Sledgehammer waits for the right bootstate.

start-up.sh has been modified to wait for the provisioner to finish
setting up the sledgehammer bootstate before trying to fetch its
control.sh instead of the previous ad-hoc methods.
Fix the OS install roles to be more reliable.

Instead of using a timeout and some hard-to-debug nohup magic to reboot
a node into its OS install environment, just wait until the provisioner
has finished doing its thing and reboot.
Update the OS post install scripts to use bootstate.

Instead to waiting 30 seconds for the provisioner to transition a node
to the local boot state, wait until it has done so before exiting the
post-install script.
Merge pull request #102 from VictorLowther/make-os-install-more-reliable

+2 Make os install more reliable