Comment 8 for bug 1611704

Ok to enumerate the tasks required to fix this:

1. Figure out ordering issues so the rabbit password can be changed on update

2. Output a password environment file in addition to the generated tripleo-overcloud-passwords file - the data contained will be the same, but the format will be directly consumable via heat similar to my example above.

3. Have the option to disable internal generation of random passwords, so the deployment will fail if an operator provided password file doesn't contain a password for a new service.