use File::Temp's unlink1 to remove SQLite's temp file

This should fix test errors in Windows which is pretty picky about
files being closed but writable before they can be unlinked.
add some more diag to Pg tests to try to find reason for smoker failues

http://www.cpantesters.org/cpan/report/82f7be78-5d65-11e4-ac7c-ffd1dfbfc7aa