remove SyncItem::GetUnionStat() from public API
remove SyncItem::GetUnionStat() from public API

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