Replaced GNU GPL with Apache2 reference (OF-65)

git-svn-id: http://svn.igniterealtime.org/svn/repos/openfire/trunk@11500 b35dd754-fafc-0310-a699-88a17e54d16e

build/build.xml

@@ -5,7 +5,7 @@
     $Revision$
     $Date$
 
-    This software is published under the terms of the GNU Public License (GPL),
+    This software is published under the terms of the Apache License, Version 2.0,
     a copy of which is included in this distribution.
 -->