Fix build failure if O_DIRECT is not defined
  Fix stack overflow by making odirect_readbuf global
  Remove soem old debug variables


storage/ndb/src/kernel/blocks/ndbfs/AsyncFile.cpp:
  Fix build failure if O_DIRECT is not defined
  Fix stack overflow by making odirect_readbuf global
  Remove soem old debug variables
storage/ndb/src/kernel/blocks/ndbfs/Ndbfs.cpp:
  Fix build failure if O_DIRECT is not defined
  Fix stack overflow by making odirect_readbuf global
  Remove soem old debug variables