api/test: fix storage pool update with only id (#11897)

Author: weizhouapache

api/src/main/java/org/apache/cloudstack/api/command/admin/storage/UpdateStoragePoolCmd.java

@@ -153,6 +153,8 @@ public void execute() {
         if (ObjectUtils.anyNotNull(name, capacityIops, capacityBytes, url, isTagARule, tags) ||
                 MapUtils.isNotEmpty(details)) {
             result = _storageService.updateStoragePool(this);
+        } else {
+            result = _storageService.getStoragePool(getId());
         }
 
         if (enabled != null) {

test/integration/smoke/test_direct_download.py

@@ -251,7 +251,10 @@ def getCurrentStoragePoolTags(self, poolId):
             self.apiclient,
             id=poolId
         )
-        return local_pool[0].tags
+        if local_pool[0].tags:
+            return local_pool[0].tags
+        else:
+            return ""
 
     def updateStoragePoolTags(self, poolId, tags):
         StoragePool.update(