[Patch] hp-systray doesn't support --qt5, but help message says it does

[zdohnal]

Hi,

we have an issue in Fedora (https://bugzilla.redhat.com/show_bug.cgi?id=1951922) regarding hp-systray. Its help page ('hp-systray -h') says:

```
[OPTIONS]
  Use Qt5: --qt5 (Default)
```

but once you run 'hp-systray --qt5', you get:

```
error: option --qt5 not recognized
```

It is because 'setUsage()' automatically creates the option in help message if hplip is compiled with GUI, 'parseStdOpt()' doesn't add it to the list of approved options.

The attached patch fixes the issue.

Ubuntu 20.04 is affected too.

[Ubuntu Foundations Team Bug Bot (crichton)]

The attachment "Proposed patch" seems to be a patch. If it isn't, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are a member of the ~ubuntu-reviewers, unsubscribe the team.

[This is an automated message performed by a Launchpad user owned by ~brian-murray, for any issues please contact him.]

[Shashank Kimothi (kim0-hplip)]

fix released in HPLIP-3.22.4