crowbar_register: Do not keep sledgehammer-specific configuration

When we first run chef-client, we need the FQDN to be resolvable, which
means we need it in /etc/hosts. But that's not something we want to
keep.

We also do not want to have "hostname" return the FQDN name anymore
after we're setup.
crowbar_join: Fix syntax error
add missing -n to zypper

crowbar_register is supposed to be non-interactive.
Revert "crowbar_join: Get the hostname before pinging the admin server"

This reverts commit f0185a468010a492d23af774a68ee09fd6109233.

If we can't ping the admin, then really, we're done. No need to enter a
loop for the hostname.
crowbar_join: Reduce time of loop for hostname

There's no point in waiting 10 minutes. If it's not there after one
minute, let's give up.
Merge pull request #304 from vuntz/fix-test

crowbar_join: Fix syntax error
Merge pull request #306 from aspiers/register-zypper-batch

add missing -n to zypper
Merge pull request #303 from vuntz/crowbar_register-fix

crowbar_register: Do not keep sledgehammer-specific configuration
Merge pull request #307 from vuntz/crowbar_join-ping-early

Avoid uselessly long loop when waiting for hostname
avoid use of /dev/disk/by-id in VirtualBox

/dev/disk/by-id is unstable under VirtualBox so we don't want to rely on
it.
Merge pull request #305 from aspiers/virtualbox-disk-by-id

avoid use of /dev/disk/by-id in VirtualBox