ndb/include/ndbapi/NdbConnection.hpp:
  Add support for removing op from list
ndb/include/ndbapi/NdbScanOperation.hpp:
  virtual destructor
ndb/src/ndbapi/NdbConnection.cpp:
  Add support for removing op from list
ndb/src/ndbapi/NdbScanOperation.cpp:
  Set magic number to invalid before first prepareSendScan
  (so that prepareSendScan is only called once incase of restarts)
ndb/src/ndbapi/Ndblist.cpp:
  Use correct type
ndb/test/src/UtilTransactions.cpp:
  Update test prg.
  - use LM_Read to maintain locks
  - set iop = null on temporary error (restart transaction)