Update oslo incubator bits

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

oslo-incubator commit 630d3959b9d001ca18bd2ed1cf757f2eb44a336f

Change-Id: I0ae9b9dc72ec88ed64a8c353b9c51734ee2cd24c
Merge branch 'review/terry_howe/bug/1100116' into dt-test
Merge branch 'oslo-clean' into dt-test
Merge branch 'image-v2-v2' into dt-test
Merge branch 'identity-ec2-tests' into dt-test