Don't show "Add network folder" button if knetattach is not available
knetattach is part of plasma-desktop, so it doesn't necessarily have to be installed. In that case, instead of showing a button that doesn't do anything, don't show it at all.
knetattach is part of plasma-desktop, so it doesn't necessarily have to be installed. In that case, instead of showing a button that doesn't do anything, don't show it at all.