fix error code to avoid clash with 5.0/5.1


ndb/include/kernel/signaldata/AlterTable.hpp:
  Change error codes to remove clash from 5.0
ndb/include/kernel/signaldata/DropTable.hpp:
  Change error codes to remove clash from 5.0
ndb/src/ndbapi/ndberror.c:
  Change error codes to remove clash from 5.0