Sync kombu_reconnect_delay from Oslo

When reconnecting to a RabbitMQ cluster
with mirrored queues in use, the attempt to release the
connection can hang "indefinitely" somewhere deep down
in Kombu.  Blocking the thread for a bit prior to
release seems to kludge around the problem where it is
otherwise reproduceable.
The value 5.0 fits for low perfomance environments as well.

Cherry-picked from Oslo.messaging:
fcd51a67d18a9e947ae5f57eafa43ac756d1a5a8
Related-bug: #856764

Change-Id: Ifadda4dd9122df9ccb4ecf560ce3db3e38adf2b9
Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

ceilometer/openstack/common/rpc/impl_kombu.py

@@ -52,6 +52,10 @@ kombu_opts = [
                default='',
                help=('SSL certification authority file '
                      '(valid only if SSL enabled)')),
+    cfg.FloatOpt('kombu_reconnect_delay',
+                 default=1.0,
+                 help='How long to wait before reconnecting in response to an '
+                      'AMQP consumer cancel notification.'),
     cfg.StrOpt('rabbit_host',
                default='localhost',
                help='The RabbitMQ broker address where a single node is used'),
@@ -495,6 +499,17 @@ class Connection(object):
             LOG.info(_("Reconnecting to AMQP server on "
                      "%(hostname)s:%(port)d") % params)
             try:
+                # NOTE(bogdando): when reconnecting to a RabbitMQ cluster
+                # with mirrored queues in use, the attempt to release the
+                # connection can hang "indefinitely" somewhere deep down
+                # in Kombu.  Blocking the thread for a bit prior to
+                # release seems to kludge around the problem where it is
+                # otherwise reproduceable.
+                if self.conf.kombu_reconnect_delay > 0:
+                    LOG.info(_("Delaying reconnect for %1.1f seconds...") %
+                             self.conf.kombu_reconnect_delay)
+                    time.sleep(self.conf.kombu_reconnect_delay)
+
                 self.connection.release()
             except self.connection_errors:
                 pass