Unleash backup to write more than 32k at a time
  Using parameter BackupMaxWriteSize
  (greatly affect LCP time in 5.1, set default value to 256k)


ndb/include/mgmapi/mgmapi_config_parameters.h:
  Add config fro max write size in backup
ndb/src/kernel/blocks/backup/BackupInit.cpp:
  Unleash backup to write more than 32k at a time
ndb/src/mgmsrv/ConfigInfo.cpp:
  Add config fro max write size in backup