[PATCH] oledb32: Support VT_NULL on all conversions (resend)

[Marvin]

Hi,

While running your changed tests on Windows, I think I found new failures.
Being a bot and all I'm not very good at pattern recognition, so I might be
wrong, but could you please double-check?
Full results can be found at
https://testbot.winehq.org/JobDetails.pl?Key=17692

Your paranoid android.


=== wvistau64 (64 bit convert) ===
convert.c:2995: Test failed: got 24

=== w2008s64 (64 bit convert) ===
convert.c:2995: Test failed: got 24

=== w7pro64 (64 bit convert) ===
convert.c:2995: Test failed: got 24

=== w864 (64 bit convert) ===
convert.c:2995: Test failed: got 24

=== w1064 (64 bit convert) ===
convert.c:2995: Test failed: got 24