minor: got rid of warning

SVN: 19333

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

@@ -100,7 +100,7 @@ class ImageGenerationDescriptionFactory
             HttpServletRequest request)
     {
         Map<String, List<String>> datasetToChannelsMap = new HashMap<String, List<String>>();
-        Enumeration params = request.getParameterNames();
+        Enumeration<?> params = request.getParameterNames();
         while (params.hasMoreElements())
         {
             String paramName = (String) params.nextElement();