EmbeddedObjectRef: guard against div by zero

With this, if dc92bac5 fails, it won't
crash, just the assertion will fail.

Change-Id: I9830094088819cade7cf47d1f25d34bb6eb52ae6

svtools/source/misc/embedhlp.cxx

@@ -658,7 +658,7 @@ void EmbeddedObjectRef::DrawPaintReplacement( const Rectangle &rRect, const OUSt
     Bitmap aBmp( SvtResId( BMP_PLUGIN ) );
     long nHeight = rRect.GetHeight() - pOut->GetTextHeight();
     long nWidth = rRect.GetWidth();
-    if( nHeight > 0 )
+    if( nHeight > 0 && aBmp.GetSizePixel().Width() > 0 )
     {
         aPt.Y() = nHeight;
         Point   aP = rRect.TopLeft();