More tmpfs impermanence fixes.

common/binary-cache-server.nix

@@ -19,6 +19,8 @@
     enable = true;
     cache = {
       hostName = config.networking.hostName;
+      # NOTE: These paths are hardcoded to /persist (not using config.custom.impermanence.persistPath)
+      # This is acceptable since this service is only enabled on btrfs-based hosts
       dataPath = "/persist/ncps/data";
       tempPath = "/persist/ncps/tmp";
       databaseURL = "sqlite:/persist/ncps/db/db.sqlite";