Unset gateway in /etc/sysconfig/network
Unset gateway in /etc/sysconfig/network

l23network Puppet module, which fuelmenu depends on,
uses gateway configuration from inside ifcfg scripts,
rather than /etc/sysconfig/network. For that reason,
it should be purged within fuelmenu to enable it to
work properly.

Change-Id: I2128f308dc94a26db32c3a6ea23a3d3cd4783640
Closes-Bug: #1430379

nebril/fuel-web,zhaochao/fuel-web,huntxu/fuel-web,zhaochao/fuel-web,nebril/fuel-web,stackforge/fuel-web,prmtl/fuel-web,prmtl/fuel-web,SmartInfrastructures/fuel-web-dev,eayunstack/fuel-web,SmartInfrastructures/fuel-web-dev,SmartInfrastructures/fuel-web-dev,prmtl/fuel-web,eayunstack/fuel-web,SmartInfrastructures/fuel-web-dev,zhaochao/fuel-web,eayunstack/fuel-web,huntxu/fuel-web,huntxu/fuel-web,nebril/fuel-web,eayunstack/fuel-web,eayunstack/fuel-web,prmtl/fuel-web,stackforge/fuel-web,huntxu/fuel-web,SmartInfrastructures/fuel-web-dev,nebril/fuel-web,prmtl/fuel-web,zhaochao/fuel-web,huntxu/fuel-web,zhaochao/fuel-web,stackforge/fuel-web,nebril/fuel-web