mgmt, cdn, directive to fix conflict naming (#17729)

Author: weidongxu-microsoft

specification/cdn/resource-manager/readme.java.md

@@ -10,6 +10,15 @@ namespace: com.microsoft.azure.management.cdn
 license-header: MICROSOFT_MIT_NO_CODEGEN
 payload-flattening-threshold: 1
 output-folder: $(azure-libraries-for-java-folder)/azure-mgmt-cdn
+
+directive:
+  - from: swagger-document
+    where: $.definitions.DeliveryRuleAction.properties.name
+    transform: >
+      $['x-ms-enum'] = {
+        "name": "DeliveryRuleActionValue",
+        "modelAsString": true
+      };
 ```
 
 ### Java multi-api