Don't use deprecated pragmas

Don't call the empty_result_callback and show_datatypes pragmas when
opening or creating a database file. The first one is marked as
deprecated in the documentation [1] and the latter one doesn't appear
there at all anymore but was removed in February 2004(!) [2].

[1] https://www.sqlite.org/pragma.html#pragma_empty_result_callbacks
[2] https://www.mail-archive.com/sqlite-users@sqlite.org/msg01252.html
Add NULL to the SQL Preferences tab