Update jsonutils.py from oslo

This fix is related to oslo-incubator commits:
3d7504b7d131fd506304c00e131ffbe821f5f992
bdef862c7b196fd6aceb081b30778a2562180264
ded9bd6d7ca88f775c0a82b8a0b7f8a1603bc1cb

Related-Bug: #1229204

Change-Id: I212c777cb8c3ca35c2f83508bd762fe31e6b9c10
Merge "Update jsonutils.py from oslo"