Adding BuckLibGenerator to autogenerate lib/BUCK

Change-Id: I7eab26f57d4f5886b1512b687fca75d684938d46
diff --git a/tools/package/BUCK b/tools/package/BUCK
index 31896f3..c02b4c9 100644
--- a/tools/package/BUCK
+++ b/tools/package/BUCK
@@ -100,10 +100,11 @@
 sources = [ '$(location :onos-features)', ]
 sources += staged_repos + staged_apps
 
+import time
 genrule(
   name = 'onos-package',
   out = 'onos.tar.gz',
-  bash = '$(exe //buck-tools:onos-stage) $OUT $(location :onos-karaf) ' + ' '.join(sources),
+  bash = 'echo %s >/dev/null; $(exe //buck-tools:onos-stage) $OUT $(location :onos-karaf) ' % time.time() + ' '.join(sources),
   visibility = [ 'PUBLIC' ],
 )