Update oslo.config
Update oslo.config

Update oslo.config to 1.2.0a3 it contains a bucket load of
python3 fixes that is needed for py3 compat in python-keystoneclient.

Change-Id: I3bc2e617b97822158ebfa39c021233557282e479
Signed-off-by: Chuck Short <753a8074f04ffd62a8fff7516e3ae689be8e35ad@canonical.com>

citrix-openstack-build/keystoneauth,jamielennox/keystoneauth,sileht/keystoneauth