nixos/kanidm: fix trying to create backup dir when server is not enabled (#459685)

nixos/modules/services/security/kanidm.nix

@@ -59,6 +59,7 @@ let
     cfg.serverSettings.tls_key
   ]
   ++ optionals cfg.provision.enable provisionSecretFiles;
+  enableServerBackup = cfg.enableServer && (cfg.serverSettings.online_backup.versions != 0);
 
   # Merge bind mount paths and remove paths where a prefix is already mounted.
   # This makes sure that if e.g. the tls_chain is in the nix store and /nix/store is already in the mount
@@ -873,7 +874,7 @@ in
 
     environment.systemPackages = mkIf cfg.enableClient [ cfg.package ];
 
-    systemd.tmpfiles.settings."10-kanidm" = {
+    systemd.tmpfiles.settings."10-kanidm" = mkIf enableServerBackup {
       ${cfg.serverSettings.online_backup.path}.d = {
         mode = "0700";
         user = "kanidm";
@@ -909,13 +910,13 @@ in
           User = "kanidm";
           Group = "kanidm";
 
-          BindPaths = [
+          BindPaths =
+            [ ]
             # To store backups
-            cfg.serverSettings.online_backup.path
-          ]
-          ++ optional (
-            cfg.enablePam && cfg.unixSettings ? home_mount_prefix
-          ) cfg.unixSettings.home_mount_prefix;
+            ++ optional enableServerBackup cfg.serverSettings.online_backup.path
+            ++ optional (
+              cfg.enablePam && cfg.unixSettings ? home_mount_prefix
+            ) cfg.unixSettings.home_mount_prefix;
 
           AmbientCapabilities = [ "CAP_NET_BIND_SERVICE" ];
           CapabilityBoundingSet = [ "CAP_NET_BIND_SERVICE" ];