PowerStore driver - Request data validation fix

Due to json.dumps({}) method returns {}, an error occurs in some
client's methods, such as when deleting volumes. This fix validate
if any payload was provided for the request.

Closes-Bug: #1981068
Change-Id: I0b389f4f53d3b34eddc23a7aebc85a5b42f3a09f

cinder/volume/drivers/dell_emc/powerstore/client.py

@@ -85,8 +85,6 @@ class PowerStoreClient(object):
                       payload=None,
                       params=None,
                       log_response_data=True):
-        if not payload:
-            payload = {}
         if not params:
             params = {}
         request_params = {
@@ -94,7 +92,7 @@ class PowerStoreClient(object):
             "verify": self._verify_cert,
             "params": params
         }
-        if method != "GET":
+        if payload and method != "GET":
             request_params["data"] = json.dumps(payload)
         request_url = self.base_url + url
         r = requests.request(method, request_url, **request_params)

releasenotes/notes/powerstore-request-data-validation-6268f2ed07b7bf40.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    PowerStore driver `bug #1981068
+    <https://bugs.launchpad.net/cinder/+bug/1981068>`_: Fixed
+    request data validation for the REST client.