getSvxBrushItemFromSourceSet: let XFILL_NONE result in COL_AUTO

I'm not completely sure about this, but without this, automatic color is
translated back as rgba(114, 159, 207, 255), which sounds even worse.

Change-Id: I9f96f26b3797d9e289119a4795d2535b6d72262e

svx/source/unodraw/unobrushitemhelper.cxx

@@ -191,10 +191,7 @@ SvxBrushItem getSvxBrushItemFromSourceSet(const SfxItemSet& rSourceSet, sal_uInt
 
     if(!pXFillStyleItem || XFILL_NONE == pXFillStyleItem->GetValue())
     {
-        // no fill, still need to rescue the evtl. set RGB color, but use as transparent color (we have XFILL_NONE)
-        Color aFillColor(static_cast< const XFillColorItem& >(rSourceSet.Get(XATTR_FILLCOLOR, bSearchInParents)).GetColorValue());
-        aFillColor.SetTransparency(0xff);
-
+        Color aFillColor(COL_AUTO);
         return SvxBrushItem(aFillColor, nBackgroundID);
     }