enable to set gateway for each ifcfg-eth.
eth -> ethernet
fix BOOTPROTO for ethernet.
enable to set gw.
ignore undefined variables with arguments.
split render_ifcfg_ethernet.
set a proper value to BOOTPROTO.
make sure to check "ip" value.
split ifcfg body before onboot.
use render_ifcfg_network_configuration.
enable to set onboot.
use render_ifcfg_network_configuration.
a bit refactoring.
move onboot parameter to upper.
Merge pull request #10 from hansode/refactor-render-ifcfg

Refactor render ifcfg