maces

change Kwallet on undetected Desktops to Kwallet5

1

This changes the used kwallet version to Backend_Kwallet5 on undetected Desktops. This enables users of LXQT to use Kwallet5. Tested and working on Archlinux https://www.archlinux.org/packages/community/x86_64/qtkeychain-qt5/ just including the above change.