ov_test/ov_test_open do not produce same results as ov_open

I first found this bug in the 1.0 release in Debian's unstable branch. I have
also confirmed that it still exists in CVS as of the filing of this bug
(08-29-2003).

Attempting to open and access an Ogg Vorbis file using ov_test() and
ov_test_open() does not produce the same results as using ov_open(). ov_open()
successfully opens the Ogg Vorbis file whereas ov_test_open() returns an
OV_EINVAL error.