Nix daemon runs in a service context, usually with systemd.
If the Nix daemon unit adds `[Service] CacheDirectory=nix-daemon`, it should
successfully use `/var/cache/nix-daemon` automatically.
Instead, it uses `/root/.cache` right now, which is really bad.
By default, we add `[Service] CacheDirectory=nix` now which means that
caches are moved into `/var/cache/nix`.
Fixes#634.
Change-Id: I854b1045bfdce8f60110aea70bda1bf6657dfd7b
Signed-off-by: Raito Bezarius <raito@lix.systems>
Raito Bezarius
1e98c01912