add `bc` utility to ubuntu
add `bc` utility to ubuntu

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