Change modificated file in rollback test
Change modificated file in rollback test

- We were trying to modify upgraders code from venv
but venv is created only after running upgrade. So now
we are modifying /upgrade/releases/metadata.yaml file.
Fix is temporary for 6.1 and will be changed to use fake
upgrader

Change-Id: Ie94bf6498f7ccc48dc17e539b72eb131e90774f4
Closes-Bug: #1402630

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