audit: Disable in containers

This barfs:

Jan 18 12:46:32 machine 522i0x9l80z7gw56iahxjjsdjp0xi10q-audit-start[506]: The audit system is disabled

nixos/modules/security/audit.nix

···
 
   config = mkIf (cfg.enable == "lock" || cfg.enable) {
     systemd.services.audit = {
-      description = "pseudo-service representing the kernel audit state";
+      description = "Kernel Auditing";
       wantedBy = [ "basic.target" ];
+
+      unitConfig.ConditionVirtualization = "!container";
 
       path = [ pkgs.audit ];
 

nixos/modules/virtualisation/container-config.nix

···
     # Shut up warnings about not having a boot loader.
     system.build.installBootLoader = "${pkgs.coreutils}/bin/true";
 
+    # Not supported in systemd-nspawn containers.
+    security.audit.enable = false;
+
   };
 
 }