Add additional checking of net type in agent
Add additional checking of net type in agent

When we call method IPAddr.new("some non api string")
it stuck on several seconds in VMware, with several
interfaces we have several minutes additional timeout.

Change-Id: I25e784eef2e471922cb5128c0cbf94eff8ba3726
Closes-bug: #1284571

zhaochao/fuel-web,koder-ua/nailgun-fcert,stackforge/fuel-web,SmartInfrastructures/fuel-web-dev,SmartInfrastructures/fuel-web-dev,eayunstack/fuel-web,stackforge/fuel-web,nebril/fuel-web,huntxu/fuel-web,koder-ua/nailgun-fcert,huntxu/fuel-web,prmtl/fuel-web,zhaochao/fuel-web,koder-ua/nailgun-fcert,huntxu/fuel-web,nebril/fuel-web,prmtl/fuel-web,prmtl/fuel-web,zhaochao/fuel-web,zhaochao/fuel-web,eayunstack/fuel-web,eayunstack/fuel-web,huntxu/fuel-web,SmartInfrastructures/fuel-web-dev,nebril/fuel-web,nebril/fuel-web,zhaochao/fuel-web,stackforge/fuel-web,SmartInfrastructures/fuel-web-dev,prmtl/fuel-web,eayunstack/fuel-web,eayunstack/fuel-web,nebril/fuel-web,huntxu/fuel-web,koder-ua/nailgun-fcert,prmtl/fuel-web,SmartInfrastructures/fuel-web-dev