Add variable, that would allow to provide extra records for /etc/hosts
file. That might be useful for ppl who still have not adopted proper
DNS or want to do DNS RR, but not for internal VIP and manage internal
VIP with /etc/hosts file, where each host group would resolve FQDN to
a local address.
Change-Id: I89f8cdebf9322c0451b5600b073c82b7773af164