Installation guide doesn't mention transport_url parameter

[Amit Bhardwaj]

This bug tracker is for errors with the documentation, use the following as a template and remove or add fields as you see fit. Convert [ ] into [x] to check boxes:

- [ ] This doc is inaccurate in this way
- [x] This is a doc addition request.: transport_url parameter is missing. Without it, CONN REFUSED errors are seen from RABBITMQ.
- [ ] I have a fix to the document that I can paste below including example: input and output.

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-----------------------------------
Release: 7.0.0.0rc2.dev3 on 2018-07-12 17:44:36
SHA: 88dacd604ab5496ea231c959fa7d83996dfc639f
Source: https://git.openstack.org/cgit/openstack/senlin/tree/doc/source/install/install-rdo.rst
URL: https://docs.openstack.org/senlin/stein/install/install-rdo.html

[Satish Patel (satish-txt)]

I am following this doc and there are couple of issue here.

Senlin use port 8778 (Not 8777)

openstack user create --project services --password-prompt senlin

This should be following

openstack user create --domain default --password-prompt senlin