Remove superfluous and erroneous imports.
Fixes #2449: CSqlDataProvider causes an error when CDbCommand with enabled PDO::FETCH_OBJ mode used as SQL source.
Data was rewritten.
Enhancement for #1604. Note about SQLite peculiarity on batch insert.
Merge pull request #2451 from resurtm/fixes-2449

Fixes #2449: CSqlDataProvider causes an error when CDbCommand with enabled PDO::FETCH_OBJ mode used as SQL source.