fixed Gentoo:Network feature from pull-request#4
commands/gnetoo/network fixing typo list.extend => list.append for _headers
commands/gnetoo/network fixing commenting for _header
fixing test test_resetnetwork_hostname for Gentoo based on RegEx
commands/gentoo/network.py corrected dns_%s var generation
commands/gentoo/network.py : for resolv fixing case for HOSTNAME
fixing commands.gentoo.network resetnetwork hostname
corrected test_resetnetwork_interfaces as per Gentoo specific pull-request changes
Merge pull request #24 from rackerlabs/gentoo-network

Gentoo Network changes and updates spiraled from Pull-Request#4