gh-2: Use GATEWAY_IFACE in rhel network
gh-2: Use GATEWAY_IFACE in rhel network

ungleich/addon-context-linux,fasrc/addon-context-linux,ungleich/addon-context-linux,baby-gnu/addon-context-linux,thomasalrin/addon-context-linux,OpenNebula/addon-context-linux,puppetmaster/addon-context-linux,baby-gnu/addon-context-linux,puppetmaster/addon-context-linux,OpenNebula/addon-context-linux,fasrc/addon-context-linux