Delete node / delete environment should use env snapshot
Delete node / delete environment should use env snapshot

It turned out there is no need to deploy simple environment
for delete xxx tests.

Change-Id: I518f861ffa8955bbe29013ca9313641a1f82fef3

dancn/fuel-main-dev,teselkin/fuel-main,SmartInfrastructures/fuel-main-dev,SmartInfrastructures/fuel-main-dev,dancn/fuel-main-dev,Fiware/ops.Fuel-main-dev,ddepaoli3/fuel-main-dev,AnselZhangGit/fuel-main,eayunstack/fuel-main,stackforge/fuel-main,zhaochao/fuel-main,AnselZhangGit/fuel-main,dancn/fuel-main-dev,zhaochao/fuel-main,stackforge/fuel-main,SergK/fuel-main,Fiware/ops.Fuel-main-dev,Fiware/ops.Fuel-main-dev,ddepaoli3/fuel-main-dev,teselkin/fuel-main,SmartInfrastructures/fuel-main-dev,dancn/fuel-main-dev,AnselZhangGit/fuel-main,SergK/fuel-main,SmartInfrastructures/fuel-main-dev,zhaochao/fuel-main,stackforge/fuel-main,Fiware/ops.Fuel-main-dev,teselkin/fuel-main,SergK/fuel-main,eayunstack/fuel-main,ddepaoli3/fuel-main-dev,AnselZhangGit/fuel-main,zhaochao/fuel-main,huntxu/fuel-main,huntxu/fuel-main,eayunstack/fuel-main,ddepaoli3/fuel-main-dev,zhaochao/fuel-main,huntxu/fuel-main,teselkin/fuel-main