Temp commit to fix breakage from googleapis#289.

Will be removed after rebasing on top of googleapis#291.

Author: dhermes

gcloud/datastore/entity.py

@@ -222,9 +222,12 @@ def save(self):
             transaction.add_auto_id_entity(self)
 
         if isinstance(key_pb, datastore_pb.Key):
-            path = [
-                {'kind': element.kind, 'id': element.id, 'name': element.name}
-                for element in key_pb.path_element]
+            path = []
+            for element in key_pb.path_element:
+                key_part = {}
+                for descriptor, value in element._fields.items():
+                    key_part[descriptor.name] = value
+                path.append(key_part)
             # Update the path (which may have been altered).
             self._key = key.path(path)