fix(impermanence): Default-persist /var/lib/nixos

As in https://github.com/nix-community/impermanence/issues/178, missing
this directory can cause folder pemissions to break after reboots

Change-Id: Ie89227ca8b2844b53a67ccd661a612192e09afd4
Reviewed-on: https://git.clicks.codes/c/Infra/NixFiles/+/789
Reviewed-by: Samuel Shuert <coded@clicks.codes>
Tested-by: Skyler Grey <minion@clicks.codes>
diff --git a/modules/nixos/clicks/storage/impermanence/default.nix b/modules/nixos/clicks/storage/impermanence/default.nix
index eb8a72e..5dd5e43 100644
--- a/modules/nixos/clicks/storage/impermanence/default.nix
+++ b/modules/nixos/clicks/storage/impermanence/default.nix
@@ -97,7 +97,9 @@
     };
 
     environment.persistence."/persist/${cfg.volumes.persistent_data}" = {
-      directories = [ ] ++ cfg.persist.directories;
+      directories = [
+        "/var/lib/nixos" # https://github.com/nix-community/impermanence/issues/178
+      ] ++ cfg.persist.directories;
       files = [
         "/etc/machine-id"
         "/etc/ssh/ssh_host_ed25519_key"