New InsertDuplicate test case in SPI checks for expected error conditions
on both transaction and operations.
merge from parent
Improve handling of errors that occur while preparing NdbOperations.
New SPI test case for unique key operations.
Use AO_Ignore for all NdbTransaction execute calls. 
Fix a bug where Record.isNull() could return true for non-nullable columns.
This could happen if a row had no nullable columns, because the null bitmap would
point one byte past the end of the record buffer.