cleaned up system tests code - leftover

SVN: 13373

rtd_phosphonetx/source/java/ch/systemsx/cisd/openbis/plugin/phosphonetx/client/web/client/application/ProteinViewer.java

@@ -312,7 +312,7 @@ public class ProteinViewer extends
         return observer;
     }
 
-    public static final class ProteinByExperimentCallback extends
+    private static final class ProteinByExperimentCallback extends
             AbstractAsyncCallback<ProteinByExperiment>
     {
         private final ProteinViewer viewer;