Updated openstack/openstack
Project: openstack/oslo.serialization  b6d2ac30d21b300c94f344aecba22777218d7c1d

Support 'built-in' datetime module

Some distributions (Ubuntu >= 14.10) build the datetime module
directly into the python interpreter; update tests to ensure that
this is detected correctly.

Change-Id: I67ebd2a29e695417fda0334952427fcf550738f2
Closes-Bug: 1369460