fix bug with not accepting write-only formats in d&d (backported from head)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_4_BRANCH@20041 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/ole/dataobj.cpp

@@ -443,7 +443,7 @@ STDMETHODIMP wxIDataObject::SetData(FORMATETC *pformatetc,
                 // as we can't fix this bug in explorer (it's a bug because it
                 // should only use formats returned by EnumFormatEtc), do the
                 // check here
-                if ( !m_pDataObject->IsSupportedFormat(format) ) {
+                if ( !m_pDataObject->IsSupported(format, wxDataObject::Set) ) {
                     // go away!
                     return DV_E_FORMATETC;
                 }