[pkg] Stop using /etc/bash_completion.d cubicweb-ctl shipped an empty /etc/bash_completion.d as a leftover of shipping a bash completion script. As pointed by Lintian, this directory is not obsolete, so let's get rid of it for good.

missing-dep-for-interpreter make => make | build-essential | dpkg-dev (usr/*/cubicweb/skeleton/debian/rules)
embedded-javascript-library usr/share/cubicweb/cubes/shared/data/jquery.js