Change ubuntu version in documentation
Change ubuntu version in documentation

Move to Ubuntu 14.04 in documentation

Change-Id: I763057b36a759a37d9663b1f4f243b90a7a75969
eayunstack/fuel-web,zhaochao/fuel-web,SmartInfrastructures/fuel-web-dev,zhaochao/fuel-web,eayunstack/fuel-web,huntxu/fuel-web,nebril/fuel-web,zhaochao/fuel-web,prmtl/fuel-web,nebril/fuel-web,prmtl/fuel-web,eayunstack/fuel-web,stackforge/fuel-web,zhaochao/fuel-web,huntxu/fuel-web,stackforge/fuel-web,huntxu/fuel-web,zhaochao/fuel-web,SmartInfrastructures/fuel-web-dev,prmtl/fuel-web,stackforge/fuel-web,nebril/fuel-web,SmartInfrastructures/fuel-web-dev,eayunstack/fuel-web,nebril/fuel-web,nebril/fuel-web,huntxu/fuel-web,prmtl/fuel-web,SmartInfrastructures/fuel-web-dev,prmtl/fuel-web,eayunstack/fuel-web,SmartInfrastructures/fuel-web-dev,huntxu/fuel-web