Update oslo incubator bits

* update gettextutils.py, strutils.py, install_venv_common.py
* remove cfg.py, openstackkeyring

oslo-incubator commit 630d3959b9d001ca18bd2ed1cf757f2eb44a336f

Change-Id: I0ae9b9dc72ec88ed64a8c353b9c51734ee2cd24c
Add API discovery and commands

* add low-level API discovery support
* add 'api list' and 'api match' commands

This is incomplete WRT other APIs, only Identity is discovered at the moment.

TODO: Fix an issue mocking the ClientManager tests with the addition of
discovery...

Change-Id: I3cdce4b2b6057efa2f517ac1e00bc8c266dcb1db
Merge branch 'oslo-clean' into dt-test
Merge branch 'image-v2-v2' into dt-test
Merge branch 'identity-ec2-tests' into dt-test