Remove too restrictive and wrong check on print test

The test was not working since commit "Removed bogus test from
_SQLRowCount" (22f466efa807a4a1f1b156b3c27a927c66e74fe3).

Signed-off-by: Frediano Ziglio <freddy77@gmail.com>
Enhance tdsdbopen logging

Open log earlier so that tdsdump_log output is seen.
Add more info to aid in diagnosing connection problems.
Add tdsdump_log when tds_connect_and_login fails.
Make some logging in dbperror more verbose.