Make the LUInstanceCreate return node names, not UUIDs

The LUInstanceCreate returned names instead of UUIDs in 2.6. Along the
way, the names were internally replaced with UUIDs, and the abstraction
leaked. This patch fixes the issue.
Signed-off-by: Hrvoje Ribicic <riba@google.com>
Reviewed-by: Thomas Thrainer <thomasth@google.com>

lib/cmdlib/instance.py

 #
 #
 
-# Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Google Inc.
+# Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014 Google Inc.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -1462,7 +1462,7 @@ class LUInstanceCreate(LogicalUnit):
                                             False, self.op.reason)
       result.Raise("Could not start instance")
 
-    return list(iobj.all_nodes)
+    return self.cfg.GetNodeNames(list(iobj.all_nodes))
 
 
 class LUInstanceRename(LogicalUnit):