Set hostname in bootstrap.sh

Also create an /etc/hosts entry, otherwise Puppet will be cranky
changes to get puppet apply on varnish to finish properly.
remote the purge_ip section ... only trouble right now.
put back in the purge_ips section, but provide empty array.
Merge pull request #5 from huit/hostname_fix

Varnish fixes + hostname_fix
Merge pull request #6 from huit/varnish-fixes

Varnish fixes