fcl-db: dbtestframework:
- revert functional changes of previous commit: better deal with NULL setting via connection/session or database level:
http://msdn.microsoft.com/en-us/library/ms174979.aspx			



git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@26949 3ad0048d-3df7-0310-abae-a5850022a9f2