FIX: add check for 'overlay' kernel module
FIX: add check for 'overlay' kernel module

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