fix potential deadlock when uploading catalogs
fix potential deadlock when uploading catalogs

djw8605/cvmfs,DrDaveD/cvmfs,cvmfs/cvmfs,cvmfs/cvmfs,djw8605/cvmfs,cvmfs/cvmfs,cvmfs/cvmfs,DrDaveD/cvmfs,cvmfs/cvmfs,Gangbiao/cvmfs,DrDaveD/cvmfs,Gangbiao/cvmfs,DrDaveD/cvmfs,djw8605/cvmfs,djw8605/cvmfs,DrDaveD/cvmfs,Gangbiao/cvmfs,cvmfs/cvmfs,Gangbiao/cvmfs,cvmfs/cvmfs,DrDaveD/cvmfs,Gangbiao/cvmfs,DrDaveD/cvmfs,djw8605/cvmfs