Conflict between podman-hpc --gpu flag and new podman --gpus flag

[danfulton]

We use argparse to validate syntax before passing it to shared run, and to separate out valid arguments for run and exec subcommands. By default argparse allows unique abbreviations of all option flags, e.g.

--foobar
--fooba
--foo
--fo

would all be equivalent if there is only a single option --foobar on a parser. Because of this behaviour, when we construct the validation parse from the podman help page, our --gpu flag is incorrectly detected as a valid abbreviation of the new podman --gpus flag.

The result is podman-hpc run does not work at all with the --gpu flag.

I believe we can tell argparse to disallow abbreviations which should solve this issue.