Migrate a single instance to another compute host in Administrator Guide

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:

- [X] This doc is inaccurate in this way:

Related to https://bugs.launchpad.net/openstack-manuals/+bug/1665860 and https://bugs.launchpad.net/openstack-manuals/+bug/1670225.

The page mixes live and cold migration without making it clear.

Some details:

Wrong text: "The scheduler chooses the destination compute host". When using the openstack client to live-migrate an instance, the user has to provide the destination host (I haven't double-checked that in Ocata, but the current OSC documentation says so).

The script in step 3 uses the "nova migrate" command instead of "openstack server migrate" and performs a cold migration, which is inconsistent with the live migration in step 2. Besides, the script could probably be simplified.
To monitor live migration, "nova server-migration-list" and "nova server-migration-show" can be used for a much simpler script.

Inconsistent text "The instance is booted from a new host" - this is true for cold migration, but not live migration.

I would rewrite the page, giving examples for cold and live migration.

- [ ] This is a doc addition request.
- [ ] I have a fix to the document that I can paste below including example: input and output.

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-----------------------------------
Release: 0.9 on 2017-03-06 05:22
SHA: ccf45727a00cc74789657833ca8947364e6f543a
Source: https://git.openstack.org/cgit/openstack/openstack-manuals/tree/doc/admin-guide/source/cli-nova-migrate.rst
URL: https://docs.openstack.org/admin-guide/cli-nova-migrate.html