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
Merge "Sync jsonutils from oslo-incubator"