Make startup work with carrot backends that doesn't have certain AMQP

connection settings.

celery/bin/celeryd.py

@@ -215,9 +215,9 @@ def run_worker(concurrency=DAEMON_CONCURRENCY, detach=False,
     # Dump configuration to screen so we have some basic information
     # when users sends e-mails.
     print(STARTUP_INFO_FMT % {
-            "vhost": settings.AMQP_VHOST,
-            "host": settings.AMQP_SERVER,
-            "port": settings.AMQP_PORT,
+            "vhost": getattr(settings, "AMQP_VHOST", "(default)"),
+            "host": getattr(settings, "AMQP_SERVER", "(default)"),
+            "port": getattr(settings, "AMQP_PORT", "(default)"),
             "exchange": conf.AMQP_EXCHANGE,
             "exchange_type": conf.AMQP_EXCHANGE_TYPE,
             "consumer_queue": conf.AMQP_CONSUMER_QUEUE,

celery/messaging.py

@@ -57,6 +57,7 @@ class TaskPublisher(Publisher):
             "retries": kwargs.get("retries", 0),
             "eta": kwargs.get("eta"),
         }
+
         if part_of_set:
             message_data["taskset"] = part_of_set