minor: do not print stack trace

SVN: 17755

screening/source/java/ch/systemsx/cisd/openbis/dss/generic/server/AbstractImagesDownloadServlet.java

@@ -165,7 +165,7 @@ abstract class AbstractImagesDownloadServlet extends AbstractDatasetDownloadServ
             }
         } catch (Exception e)
         {
-            e.printStackTrace();
+            //e.printStackTrace();
             printErrorResponse(response, "Error: " + e.getMessage());
         }