FIX: unwanted assertion replaced by usual error message + FIX: race condition
FIX: unwanted assertion replaced by usual error message + FIX: race condition

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