Do not append download target dir to entry files

While working on the KRunner store I noticed that the target dir of the entries gets written to each entry as an installed file.

This is especially problematic, because we are passing in each installed file to the uninstall script.

Before the entries installed files would look like this:

<installedfile>/home/user/.local/share/krunner-sources/vbox-runner-0.3.3/*</installedfile>
<installedfile>/home/user/.local/share/krunner-sources//</installedfile>

!26 (merged) should land before this, otherwise we might have unwanted behavior in some cases ;-)

@ngraham @leinir