Modify the unhelpful error message when delete network

Openstackclient returns a dump of the network object which is
unhelpful when Network delete error.
The patch deletes unhelpful object message and exposes real error
messages.
story: 2001973

Change-Id: Id3f20214d034848d36f9b6c8c9c73ef66ad26cdd

openstack/proxy.py

@@ -138,15 +138,7 @@ class Proxy(six.with_metaclass(_meta.ProxyMeta, _adapter.OpenStackSDKAdapter)):
         res = self._get_resource(resource_type, value, **attrs)
 
         try:
-            rv = res.delete(
-                self,
-                error_message=(
-                    "Unable to delete {resource_type} for {value}".format(
-                        resource_type=resource_type.__name__,
-                        value=value,
-                    )
-                )
-            )
+            rv = res.delete(self)
         except exceptions.NotFoundException:
             if ignore_missing:
                 return None

openstack/tests/unit/test_proxy.py

@@ -175,11 +175,11 @@ class TestProxyDelete(base.TestCase):
 
     def test_delete(self):
         self.sot._delete(DeleteableResource, self.res)
-        self.res.delete.assert_called_with(self.sot, error_message=mock.ANY)
+        self.res.delete.assert_called_with(self.sot)
 
         self.sot._delete(DeleteableResource, self.fake_id)
         DeleteableResource.new.assert_called_with(id=self.fake_id)
-        self.res.delete.assert_called_with(self.sot, error_message=mock.ANY)
+        self.res.delete.assert_called_with(self.sot)
 
         # Delete generally doesn't return anything, so we will normally
         # swallow any return from within a service's proxy, but make sure