simplify the task steering method in MigrationWorker
simplify the task steering method in MigrationWorker

djw8605/cvmfs,Gangbiao/cvmfs,reneme/cvmfs,MicBrain/cvmfs,alhowaidi/cvmfsNDN,bbockelm/cvmfs,reneme/cvmfs,DrDaveD/cvmfs,trshaffer/cvmfs,reneme/cvmfs,cvmfs-testing/cvmfs,reneme/cvmfs,alhowaidi/cvmfsNDN,Gangbiao/cvmfs,djw8605/cvmfs,bbockelm/cvmfs,Gangbiao/cvmfs,djw8605/cvmfs,Gangbiao/cvmfs,djw8605/cvmfs,cvmfs/cvmfs,DrDaveD/cvmfs,DrDaveD/cvmfs,trshaffer/cvmfs,cvmfs/cvmfs,cvmfs-testing/cvmfs,cvmfs/cvmfs,Moliholy/cvmfs,cvmfs-testing/cvmfs,trshaffer/cvmfs,alhowaidi/cvmfsNDN,bbockelm/cvmfs,bbockelm/cvmfs,MicBrain/cvmfs,trshaffer/cvmfs,Moliholy/cvmfs,DrDaveD/cvmfs,Moliholy/cvmfs,reneme/cvmfs,bbockelm/cvmfs,cvmfs/cvmfs,cvmfs/cvmfs,alhowaidi/cvmfsNDN,Moliholy/cvmfs,Moliholy/cvmfs,Gangbiao/cvmfs,cvmfs-testing/cvmfs,cvmfs-testing/cvmfs,cvmfs/cvmfs,trshaffer/cvmfs,djw8605/cvmfs,MicBrain/cvmfs,DrDaveD/cvmfs,DrDaveD/cvmfs,MicBrain/cvmfs,MicBrain/cvmfs,alhowaidi/cvmfsNDN,DrDaveD/cvmfs,cvmfs/cvmfs