add sync-flag to FsAppendReq


storage/ndb/include/kernel/signaldata/FsAppendReq.hpp:
  Add sync flag to FsAppend
storage/ndb/include/kernel/signaldata/FsOpenReq.hpp:
  Add auto sync flag to FSOPEN
storage/ndb/src/kernel/blocks/ndbfs/AsyncFile.cpp:
  Add append_synch and auto sync
storage/ndb/src/kernel/blocks/ndbfs/AsyncFile.hpp:
  Add variables for auto sync
storage/ndb/src/kernel/blocks/ndbfs/Ndbfs.cpp:
  Add append_sync and auto sync