Universal java installer cannot create linux shotcut properly

[kanglinyao]

The quelea 2020 beta version cannot create linux shotcut properly in menu or desktop. Manjaro and Arch linux.

[berry120]

We haven't tested on Arch, so there's likely to be the odd thing like this that doesn't work too well. Sample applies as #258 really - more than happy to receive PRs to fix stuff like this so long as they don't cause breaking changes elsewhere, but it's unlikely the core devs will get around to looking at this any time soon I'm afraid.