Add payload base classes to prepare for simplifying the client

This change adds payload request and response base classes to
prepare for future simplification updates to the current client
architecture. No new tests are required for this change.

kmip/core/messages/payloads/revoke.py

@@ -17,13 +17,11 @@ from kmip.core import attributes
 from kmip.core import enums
 from kmip.core import objects
 from kmip.core import primitives
-
-from kmip.core.primitives import Struct
-
+from kmip.core.messages.payloads import base
 from kmip.core.utils import BytearrayStream
 
 
-class RevokeRequestPayload(Struct):
+class RevokeRequestPayload(base.RequestPayload):
     """
     A request payload for the Revoke operation.
 
@@ -51,8 +49,7 @@ class RevokeRequestPayload(Struct):
             compromise_occurrence_date (DateTime): the datetime when the object
                 was first believed to be compromised.
         """
-        super(RevokeRequestPayload, self).__init__(
-            tag=enums.Tags.REQUEST_PAYLOAD)
+        super(RevokeRequestPayload, self).__init__()
         self.unique_identifier = unique_identifier
         self.compromise_occurrence_date = compromise_occurrence_date
         self.revocation_reason = revocation_reason
@@ -145,7 +142,7 @@ class RevokeRequestPayload(Struct):
             raise TypeError(msg)
 
 
-class RevokeResponsePayload(Struct):
+class RevokeResponsePayload(base.ResponsePayload):
     """
     A response payload for the Revoke operation.
     The payload contains the server response to the initial Revoke request.
@@ -161,8 +158,7 @@ class RevokeResponsePayload(Struct):
             unique_identifier (UniqueIdentifier): The UUID of a managed
                 cryptographic object.
         """
-        super(RevokeResponsePayload, self).__init__(
-            tag=enums.Tags.RESPONSE_PAYLOAD)
+        super(RevokeResponsePayload, self).__init__()
         if unique_identifier is None:
             self.unique_identifier = attributes.UniqueIdentifier()
         else: