Fix Should-Start of crowbar_join init script

We do not need keystone and neutron there as the cookbooks will start
them.

However, we need neutron-ovs-cleanup as if it has to run before, to not
break neutron that we will start.
Use the right provides for crowbar_join init script
Run insserv for crowbar_join if the init script got changed

This makes sure the dependency graph for starting services is updated.
Merge pull request #276 from vuntz/fix-crowbar_join

Fix crowbar_join init script