fcl-db: odbc: fix NULL numeric parameter handling for MS SQL Server

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@24391 3ad0048d-3df7-0310-abae-a5850022a9f2
fcl-db/dbase: cosmetic

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@24392 3ad0048d-3df7-0310-abae-a5850022a9f2