Comment 2 for bug 1676989

There's two issues with that one StrOpt that I've identified.

Firstly, marking it as both positional and required results in an argparse argument that is positional and optional.

Secondly, including a hyphen in the option name results in a hyphen in the destination variable name in the argument namespace (unlike other destinations produced by oslo_config.cfg), making oslo_config.cfg unable to later retrieve the value (because it's retrieving the intended destination, with an underscore, rather than the actual destination, with a hyphen).