Shaker does not support selection of individual compute hosts

[Phil Sphicas]

Issue:

It is not possible to choose specific compute hosts for agent deployment.

Shaker should allow the use of the availability_zone:compute_host syntax that is supported by Heat and the Openstack CLI.

To replicate:

Specify a valid availability zone and compute host combination in shaker.cfg

scenario_availability_zone = nova:mtn13r10c002

Observe the deployment error "Not enough compute nodes []":

2018-12-06 14:07:06.934 5220 ERROR __main__ DeploymentException: Not enough compute nodes [] for requested instance accommodation {'compute_nodes': 1, 'single_room': True, 'zones': ['nova:mtn13r10c002']}

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/623342
Committed: https://git.openstack.org/cgit/openstack/shaker/commit/?id=249ad453a490b56e528a468391a2d32ff29b93de
Submitter: Zuul
Branch: master

commit 249ad453a490b56e528a468391a2d32ff29b93de
Author: Sphicas, Phil (ps3910) <email address hidden>
Date: Thu Dec 6 14:24:57 2018 -0800

    Allow granular host selection

    This commit is to allow the use of the following syntax in the
    scenario_availability_zone parameter:

    scenario_availability_zone = availability_zone:compute_host

    Change-Id: I5b93d1083ce019e1d61199ad6d7b8b478a5678b9
    Closes-Bug: 1807278