Change Jar so empty jars are not rebuilt

PR:	6069
Submitted by:	jesse.glick@netbeans.com (Jesse Glick)


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@271136 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -370,7 +370,7 @@ public class Jar extends Zip {
         
     protected boolean createEmptyZip(File zipFile) {
         // Jar files always contain a manifest and can never be empty        
-        return false;
+        return true;
     }
     
     /**