Merge pull request #4715 from rtfd/reduce-cname-404-logs

Reduce the logging we do on CNAME 404

Author: ericholscher

readthedocs/core/middleware.py

@@ -117,7 +117,7 @@ def process_request(self, request):
                         **log_kwargs))
                 except:  # noqa
                     # Some crazy person is CNAMEing to us. 404.
-                    log.exception(LOG_TEMPLATE.format(msg='CNAME 404', **log_kwargs))
+                    log.debug(LOG_TEMPLATE.format(msg='CNAME 404', **log_kwargs))
                     raise Http404(_('Invalid hostname'))
         # Google was finding crazy www.blah.readthedocs.org domains.
         # Block these explicitly after trying CNAME logic.