Remove extraneous call of hostname conversion

Author: Slavek Kabrda

datadog_callback.py

@@ -339,7 +339,6 @@ def playbook_on_stats(self, stats):
             event_title += ' with errors'
             event_text += "\nErrors occurred on the following hosts:\n%%%\n"
             for host, failures, unreachable in error_hosts:
-                host = self.get_dd_hostname(host)
                 event_text += "- `{0}` (failure: {1}, unreachable: {2})\n".format(
                     host,
                     failures,