Don't LOG.error on max_depth (by default).

Reverts part of 7b206ad which added an extra LOG.error
statement when max_depth is hit.

This is causing spurious errors to get logged when making
some Nova requests.

Fixes LP Bug #1140133

Change-Id: I0fff47d9c53c63345ae273a4d20a2bacb27f12e5

nova/openstack/common/jsonutils.py

@@ -38,14 +38,10 @@ import functools
 import inspect
 import itertools
 import json
-import logging
 import xmlrpclib
 
-from nova.openstack.common.gettextutils import _
 from nova.openstack.common import timeutils
 
-LOG = logging.getLogger(__name__)
-
 
 def to_primitive(value, convert_instances=False, convert_datetime=True,
                  level=0, max_depth=3):
@@ -85,8 +81,6 @@ def to_primitive(value, convert_instances=False, convert_datetime=True,
         return 'mock'
 
     if level > max_depth:
-        LOG.error(_('Max serialization depth exceeded on object: %d %s'),
-                  level, value)
         return '?'
 
     # The try block may not be necessary after the class check above,