Sync jsonutils from oslo-incubator

Included commits:
commit ad248f66 Specify namedtuple_as_object=False when using simplejson
commit ef37e032 Added missing jsonutils.dump() function

My motivation of sync is the following neutron change.
https://review.openstack.org/#/c/112178/

Closes-Bug: #1356173
Change-Id: I0086e5ffa27fa5035112d4868aeb14cbdfa8f4de

oslo/messaging/openstack/common/jsonutils.py

@@ -38,11 +38,13 @@ import inspect
 import itertools
 import sys
 
+is_simplejson = False
 if sys.version_info < (2, 7):
     # On Python <= 2.6, json module is not C boosted, so try to use
     # simplejson module if available
     try:
         import simplejson as json
+        is_simplejson = True
     except ImportError:
         import json
 else:
@@ -165,9 +167,17 @@ def to_primitive(value, convert_instances=False, convert_datetime=True,
 
 
 def dumps(value, default=to_primitive, **kwargs):
+    if is_simplejson:
+        kwargs['namedtuple_as_object'] = False
     return json.dumps(value, default=default, **kwargs)
 
 
+def dump(obj, fp, *args, **kwargs):
+    if is_simplejson:
+        kwargs['namedtuple_as_object'] = False
+    return json.dump(obj, fp, *args, **kwargs)
+
+
 def loads(s, encoding='utf-8', **kwargs):
     return json.loads(strutils.safe_decode(s, encoding), **kwargs)