ndb/src/mgmclient/CommandInterpreter.cpp:
  Modify error message from "Start of backup failed" to "Backup failed" when backup is aborted
ndb/src/mgmsrv/Services.cpp:
  Append error message when error event occour
ndb/src/ndbapi/ndberror.c:
  Mofidy error message from "Backup aborted by applicaton" to "Backup aborted by user request"