client: Enable big_writes only for Fuse >= 2.8.
client: Enable big_writes only for Fuse >= 2.8.

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