Fix -x argument to create-versioned-image (thanks Mike!).

clientside/tmcc/linux/xen/create-xen-image

 #!/usr/bin/perl -w
 #
-# Copyright (c) 2000-2014 University of Utah and the Flux Group.
+# Copyright (c) 2000-2015 University of Utah and the Flux Group.
 # 
 # {{{EMULAB-LICENSE
 # 
@@ -200,7 +200,7 @@ else {
 	unshift(@ARGV, "DISK=$device");
 	unshift(@ARGV, "PROXY=$vnodeid");
 
-	$cmd = "$VIMAGE -x @ARGV";
+	$cmd = "$VIMAGE -x $vnodeid @ARGV";
     }
     else {
 	$cmd = "$zipper " . ($slice ? "-s $slice " : "") . "$device $filename ";