UnknownElement set the created task to null for gc , but did not

set the RuntimeConfigurable's copy to null as well


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@275840 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/UnknownElement.java

@@ -309,6 +309,7 @@ public class UnknownElement extends Task {
         // the task will not be reused ( a new init() will be called )
         // Let GC do its job
         realThing = null;
+        getWrapper().setProxy(null);
     }
 
     /**