Add ip address and FQDN to /etc/hosts

ubuntu, debian:
 * http://www.debian.org/doc/manuals/debian-reference/ch05.en.html#_the_hostname_resolution

redhat, centos:
 * http://www.rackspace.com/knowledge_center/article/centos-hostname-change

gentoo:
 * http://en.gentoo-wiki.com/wiki/Fully_Qualified_Domain_Name_Configuration