RabbitMQ is not using erlang port mapper managed by systemd

[Alexey Lebedeff]

Detailed bug description:
  After installing master node from fuel-9.0-mos-361-2016-05-14_12-18-00.iso, it could be seen that epmd (erlang port mapper) is running under 'rabbitmq' user, while it should run under separated user 'epmd' and be managed by systemd.

Steps to reproduce:
 Just install the master node

Expected results:
  "ps axu | grep epmd" should report epmd as a process running under 'epmd' user

Actual result:
 "ps axu | grep epmd" shows that epmd is running under 'rabbitmq' user
 <put your information here>

Reproducibility:
 100%

Impact:
 It should have no impact on completely standard installation. But any attempt to mess with additional erlang-based software can go wrong, and this can cause some random and hard-to-debug failures.

Description of the environment:
 rabbitmq-server packages version is 3.6.1-6.el7~mos1

Additional info:
 Upstream fix https://github.com/rabbitmq/rabbitmq-server/pull/801

[Fuel Devops McRobotson (fuel-devops-robot)]

Change abandoned by Alexey Lebedeff <email address hidden> on branch: master
Review: https://review.fuel-infra.org/20731
Reason: Test are moved to separate repository

[Dmitry Mescheryakov (dmitrymex)]

We discussed the issue with Alexey and decided that we will not make that change in 9.x, where we still use Ubuntu Trusty on OpenStack nodes. The issue will be fixed only on 10.0 which goes with Xenial.