cloud-init module: fix default settings (#231867)

The `//` operator doesn't do deep merge so it was overriding the first
attrset and not recording the defaults.

nixos/modules/services/system/cloud-init.nix

@@ -90,7 +90,7 @@ in
 
   };
 
-  config = {
+  config = mkIf cfg.enable {
     services.cloud-init.settings = {
       system_info = mkDefault {
         distro = "nixos";
@@ -142,7 +142,6 @@ in
         "power-state-change"
       ];
     };
-  } // (mkIf cfg.enable {
 
     environment.etc."cloud/cloud.cfg" =
       if cfg.config == "" then
@@ -225,5 +224,7 @@ in
       description = "Cloud-config availability";
       requires = [ "cloud-init-local.service" "cloud-init.service" ];
     };
-  });
+  };
+
+  meta.maintainers = [ maintainers.zimbatm ];
 }