Update copyright date.

tbsetup/libvtop_stable.pm.in

 #!/usr/bin/perl -w
 #
 # EMULAB-COPYRIGHT
-# Copyright (c) 2005-2011 University of Utah and the Flux Group.
+# Copyright (c) 2005-2012 University of Utah and the Flux Group.
 # All rights reserved.
 #
 package libvtop_stable;