Somehow in the code reorganisation of
11da2a6c9b the check for --min-age and
--max-age got switched around. This commit fixes that and means you
can use --min-age and --max-age together.
The purpose of this is to make it easier to maintain and eventually to
allow the rclone backends to be re-used in other projects without
having to use the rclone configuration system.
The new code layout is documented in CONTRIBUTING.
