fcl-db: bufdataset: improve rev.26604. do not use Field.SetData in BlobStream constructor, because SetData also calls Validate and generates deFieldChange. Which is too early in constructor. These events must be generated after data will be written (in fact deFieldChange is called in BlobStream destructor and Validate is not called in current implementation).
Instead of Field.SetData I use direct write to record buffer.

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@26611 3ad0048d-3df7-0310-abae-a5850022a9f2