change type of cluster_id in run_ostf_method
change type of cluster_id in run_ostf_method

Fix 500 error on invokation of run_ostf method

Change-Id: Ica8c6106a96d3b75b84f613d878fbeb4a7f1124c

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