Log Message:
Update net/rabbitmq to 3.5.5.

- Various performance improvements in the server
- Reduce default heartbeat interval from 580 to 60 seconds
- Force essential TCP options, especially {reuseaddr, true}.
- Catch SIGTERM and other signals in the rabbitmq-server script to stop
  RabbitMQ gracefully
- Fix a queue hang when a slave node is lost
- Fix a crash during startup when RabbitMQ tries to clean non-existing
  bindings
- Support backticks in the password field when adding a user with
  rabbitmqctl on Unix
- Fix a problem in gen_server2 causing calls to timeout under certain
  conditions
- Federation: Fix a crash when certain headers are already present
  in the forwarded message
- Federation: Increase reconnection delay from 1 to 5 seconds
- Federation: Ignore federation-specific headers added by clients
- Management UI: Do not consider non-UTF-8 content as invalid
- Management UI: Split long Base64 content in multiple lines
- Management UI: Fix a bug with rounding moving averages
- MQTT: Coerce default_user, default_pass, exchange and vhost to
  Erlang binaries
- Stomp: Set the redelivered header to a boolean value
- Stomp: Properly propagate extensions headers (x-headers) in
  the SUBSCRIBE and SEND frames
- Stomp: Duplicate subscription IDs no longer result in unhandled
  exceptions

Full release notes:

  https://github.com/rabbitmq/rabbitmq-server/releases/tag/rabbitmq_v3_5_5