Fix the OCSP test on Windows

The windows test uses the pseudo file "nul" to indicate no file for the
-CApath option. This does not work on all versions of Windows. Instead use
the new -no-CApath option.

Reviewed-by: Andy Polyakov <appro@openssl.org>

test/recipes/80-test_ocsp.t

@@ -27,7 +27,7 @@ sub test_ocsp {
 				"-partial_chain", @check_time,
 				"-CAfile", catfile($ocspdir, $CAfile),
 				"-verify_other", catfile($ocspdir, $CAfile),
-				"-CApath", devnull()]))),
+				"-no-CApath"]))),
 		  $title); });
 }