FIX: double check for open FDs on `rollback()`
FIX: double check for open FDs on `rollback()`

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