nova-manage db purge -h has weird help for --before option

[Matt Riedemann]

This is probably due to not having a metavar defined for the --before option, but the help output is weird:

stack@stein:~/nova$ nova-manage db purge -h
/usr/local/lib/python2.7/dist-packages/psycopg2/__init__.py:144: UserWarning: The psycopg2 wheel package will be renamed from release 2.8; in order to keep installing from binary please use "pip install psycopg2-binary" instead. For details see: <http://initd.org/psycopg/docs/install.html#binary-install-from-pypi>.
  """)
usage: nova-manage db purge [-h] [--before ACTION_KWARG_BEFORE] [--all]
                            [--verbose] [--all-cells]

optional arguments:
  -h, --help show this help message and exit
  --before ACTION_KWARG_BEFORE
                        If specified, purge rows from shadow tables that are
                        older than this. Fuzzy time specs are allowed
  --all Purge all rows in the shadow tables
  --verbose Print information about purged records
  --all-cells Run against all cell databases
stack@stein:~/nova$

Notably the "ACTION_KWARG_BEFORE" thing.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/616723

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/616723
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=dda614c7722973a200278c37ace569cd056d5f50
Submitter: Zuul
Branch: master

commit dda614c7722973a200278c37ace569cd056d5f50
Author: Takashi NATSUME <email address hidden>
Date: Fri Nov 9 10:43:15 2018 +0900

    Fix a help string in nova-manage

    Fix a help string of the '--before' argument
    in the 'nova-manage db purge' command.

    Change-Id: I21845c52e09bb794e52bd7375fb70a498aab92ed
    Closes-Bug: #1802167

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/nova 19.0.0.0rc1 release candidate.