ndb/src/ndbapi/ndberror.c:
  distinguish blob method errors: 4265-wrong state 4275-wrong op type/lockmode
ndb/src/ndbapi/NdbBlobImpl.hpp:
  distinguish blob method errors: 4265-wrong state 4275-wrong op type/lockmode
  fix 4269 -> 4270
ndb/test/ndbapi/testBlobs.cpp:
  test lock upgrade, test 4275 errors
ndb/include/ndbapi/NdbScanOperation.hpp:
  fix comment
ndb/include/ndbapi/NdbBlob.hpp:
  upgrade LM_CommittedRead to LM_Read
  check if write allowed (new error 4275)
  dont invalidate blob state on error (just general principle)
ndb/src/ndbapi/NdbBlob.cpp:
  upgrade LM_CommittedRead to LM_Read
  check if write allowed (new error 4275)
  dont invalidate blob state on error (just general principle)