Avoid ValueError on null endpoints subsets.

This is a hacky workaround for:
kubernetes-client#376

The client code is generated and should not be manually edited like
this, but the error is blocking our use of the library.

Author: jgiles

kubernetes/client/models/v1_endpoints.py

@@ -152,9 +152,6 @@ def subsets(self, subsets):
         :param subsets: The subsets of this V1Endpoints.
         :type: list[V1EndpointSubset]
         """
-        if subsets is None:
-            raise ValueError("Invalid value for `subsets`, must not be `None`")
-
         self._subsets = subsets
 
     def to_dict(self):