mirror/ubuntu: fix silly typo in repo.mk
mirror/ubuntu: fix silly typo in repo.mk

Solves ISO build failure

Change-Id: I126de34bcb1c66b3e0fb7210f695e7c06e172142

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