The --before option to nova manage db purge and archive_deleted_rows
accepts a string to be parsed by dateutils.parser.parse() with
fuzzy=True. This is fairly forgiving, but doesn't handle e.g. "now - 1
day". This commit adds some clarification to the help strings, and some
examples to the docs.
Change-Id: Ib218b971784573fce16b6be4b79e0bf948371954
d8ad9f986e