Pass all datetime values to pyodbc for timezone-naive column

Pass all datetime values to pyodbc for timezone-naive column

Fixed regression caused by :ticket:`6306` which added support for
``DateTime(timezone=True)``, where the previous behavior of the pyodbc
driver of implicitly dropping the tzinfo from a timezone-aware date when
INSERTing into a timezone-naive DATETIME column were lost, leading to a SQL
Server error when inserting timezone-aware datetime objects into
timezone-native database columns.

Fixes: #6366
Change-Id: Id7821de13d75ede27f2165b37277a7223468dfa4