coverity#735654 avoid division by 0

Change-Id: If368d300c5ed880e1359cbc67df0e13b00fc6ecf

vcl/source/control/combobox.cxx

@@ -1114,7 +1114,7 @@ void ComboBox::GetMaxVisColumnsAndLines( sal_uInt16& rnCols, sal_uInt16& rnLines
     else
     {
         Size aOutSz = mpSubEdit->GetOutputSizePixel();
-        rnCols = (sal_uInt16)(aOutSz.Width()/nCharWidth);
+        rnCols = (nCharWidth > 0) ? (sal_uInt16)(aOutSz.Width()/nCharWidth) : 1;
         rnLines = 1;
     }
 }