clean up at the end of execute so that this instance can be reused.

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@271579 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/taskdefs/Copy.java

@@ -318,6 +318,9 @@ public class Copy extends Task {
         if (destFile != null) {
             destDir = null;
         }
+        fileCopyMap.clear();
+        dirCopyMap.clear();
+        completeDirMap.clear();
     }
 
 //************************************************************************