Symbolic link from etc/xwiki/xwiki-locales.txt to /usr/lib/xwiki/WEB-INF is missing

This seems not to be a real problem but causes misleading warnings in the log every time one visits the Localization section in the Wiki Admin.

See e.g. this forum post:  https://forum.xwiki.org/t/applications-macros-are-not-executed-after-update-form-11-5-to-11-6/5331

I found the place to fix it, but as I have little experience withe the Debian build and no idea how to test it, so I better send a pull request.