fuelmenu: check for APT repos only if Ubuntu based bootstrap is enabled
fuelmenu: check for APT repos only if Ubuntu based bootstrap is enabled

So the master node can be deployed without an Internet access if the
CentOS based bootstrap is used (which is the default).

Related-Bug: #1487044
Change-Id: I9e984e458a372478b8705b9b4440e4d502024391

eayunstack/fuel-web,eayunstack/fuel-web,SmartInfrastructures/fuel-web-dev,huntxu/fuel-web,SmartInfrastructures/fuel-web-dev,huntxu/fuel-web,SmartInfrastructures/fuel-web-dev,huntxu/fuel-web,stackforge/fuel-web,eayunstack/fuel-web,eayunstack/fuel-web,SmartInfrastructures/fuel-web-dev,eayunstack/fuel-web,stackforge/fuel-web,huntxu/fuel-web,stackforge/fuel-web,SmartInfrastructures/fuel-web-dev,huntxu/fuel-web