6781784: Fix ant link in build readme

Reviewed-by: michaelm

README-builds.html

@@ -839,7 +839,7 @@
             <blockquote>
                 All OpenJDK builds require access to least Ant 1.6.5.
                 The Ant tool is available from the 
-                <a href="http://ant.apache.org/antlibs/bindownload.cgi" target="_blank">
+                <a href="http://ant.apache.org" target="_blank">
                 Ant download site</a>.
                 You should always make sure <tt>ant</tt> is in your PATH, and
                 on Windows you may also need to set