Don't build the Netbeans Installer modules.

--- a/nbbuild/cluster.properties
+++ b/nbbuild/cluster.properties
@@ -758,8 +758,6 @@
         apisupport.harness,\
         jellytools.platform,\
         jemmy,\
-        libs.nbi.ant,\
-        libs.nbi.engine,\
         nbjunit,\
         o.n.insane