fix memory leak during library unload
fix memory leak during library unload

Gangbiao/cvmfs,DrDaveD/cvmfs,djw8605/cvmfs,alhowaidi/cvmfsNDN,cvmfs/cvmfs,reneme/cvmfs,cvmfs/cvmfs,DrDaveD/cvmfs,cvmfs/cvmfs,Gangbiao/cvmfs,cvmfs/cvmfs,trshaffer/cvmfs,djw8605/cvmfs,Gangbiao/cvmfs,alhowaidi/cvmfsNDN,Gangbiao/cvmfs,DrDaveD/cvmfs,cvmfs/cvmfs,trshaffer/cvmfs,djw8605/cvmfs,djw8605/cvmfs,reneme/cvmfs,DrDaveD/cvmfs,reneme/cvmfs,Gangbiao/cvmfs,alhowaidi/cvmfsNDN,cvmfs/cvmfs,reneme/cvmfs,DrDaveD/cvmfs,alhowaidi/cvmfsNDN,reneme/cvmfs,alhowaidi/cvmfsNDN,DrDaveD/cvmfs,trshaffer/cvmfs,DrDaveD/cvmfs,cvmfs/cvmfs,trshaffer/cvmfs,trshaffer/cvmfs,djw8605/cvmfs