Comment # 21 on bug 1078466 from Franck Bui

After discussing this with Jean, it appears that defining 2 rules for the same
path in different conf files is error prone and should be avoided.

So I'm re-opening this bug in order to fix it properly.

I'll probably drop the definitions in tmp.conf (shipped by systemd) so the
rules defined by filesystem are the only isntalled ones.