client: Volume: changed f_blocks calculation
client: Volume: changed f_blocks calculation

gurkerl83/millipede-xtreemfs,gurkerl83/millipede-xtreemfs,gurkerl83/millipede-xtreemfs,gurkerl83/millipede-xtreemfs,gurkerl83/millipede-xtreemfs,gurkerl83/millipede-xtreemfs,gurkerl83/millipede-xtreemfs