make DirectoryEntry::GetSpecial() a const method
make DirectoryEntry::GetSpecial() a const method

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