cluster/services/incandescence: fix script when nothing will be created or changed

cluster/services/incandescence/provider.nix

@@ -39,6 +39,9 @@ in
               fi
             ''))
             (concatStringsSep "\n")
+            (script: if script == "" then ''
+              echo "Nothing to create"
+            '' else script)
           ];
         };
         "ignite-${provider}-${formula}-change" = mkIf (formulaConfig.change != null) {
@@ -58,6 +61,9 @@ in
               ) || echo "Change failed: ${object}"
             ''))
             (concatStringsSep "\n")
+            (script: if script == "" then ''
+              echo "Nothing to change"
+            '' else script)
           ];
         };
         "ignite-${provider}-${formula}-destroy" = {