MONDRIAN: Make sure the plug-in is cleared after the test, to avoid t…

…hat other tests could be somehow be affected.

[git-p4: depot-paths = "//open/mondrian/": change = 8529]

testsrc/main/mondrian/rolap/DataSourceChangeListenerTest.java

@@ -123,6 +123,7 @@ public void testDataSourceChangeListenerPlugin() {
             sqlLogger.clear();                            
             assertEquals(s4,s5);                                               
         } finally {
+            smr.changeListener = null;
             RolapUtil.threadHooks.set(null);
         }                
 }