Fix SHA for pasystray.

[mdorman]

I presume there's something about how github creates the .zip files such
that they can change SHA.

Please note: this is a very outdated version of pasystray---I don't know
if that's intentional, but perhaps a better strategy would be to update
it wholesale.

[mdorman]

And, in fact, this now updates to the latest version of pasystray, which I've built and tested locally.

[lucabrunox]

Use fetchzip.

[mdorman]

@lethalman updated.

[copumpkin]

I'd suggest using fetchFromGitHub, which uses fetchzip but also abstracts out common things, so if issues arise in future we can fix (almost) all GH fetches in one place.

[lucabrunox]

Thanks.