logstash: new input for msgpack over UDP
msgpack is a binary serialization format (http://msgpack.org/). It can
be used to exchange JSON like data between systems/languages. uWSGI
includes some nice instructions for logging to a Logstash cluster with
msgpack encoded messages:
http://uwsgi-docs.readthedocs.io/en/latest/LogEncoders.html#the-msgpack-encoder
Bug: T143172
Change-Id: I4d6d912e7d6d77e7cbfa276ad4b7e0c693d920c0