qapi: Use OrderedDict from standard library if available

The OrderedDict class appeared in the 'collections' module
from python 2.7 onwards, so use that in preference to our
local backport if available.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <20180116134217.8725-4-berrange@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

scripts/qapi.py

@@ -18,7 +18,10 @@ import os
 import re
 import string
 import sys
-from ordereddict import OrderedDict
+try:
+    from collections import OrderedDict
+except:
+    from ordereddict import OrderedDict
 
 builtin_types = {
     'null':     'QTYPE_QNULL',