Add listener service for event alarm evaluation

[OpenStack Infra]

https://review.openstack.org/200974

Dear documentation bug triager. This bug was created here because we did not know how to map the project name "openstack/aodh" to a launchpad project name. This indicates that the notify_impact config needs tweaks. You can ask the OpenStack infra team (#openstack-infra on freenode) for help if you need to.

commit 87da652820b8595a548f421c4beb278756a15d36
Author: Ryota MIBU <email address hidden>
Date: Wed Aug 19 23:27:20 2015 +0900

    Add listener service for event alarm evaluation

    This patch adds an event listener service which listens event queue and
    triggers evaluations of 'event' type alarms.

    DocImpact

    Change-Id: I5ee00ab50a0181bacee6d037ce61f40c1eddcfa2
    Implements: blueprint event-alarm-evaluator

[Joseph Robinson (joseph-r-email)]

affects http://docs.openstack.org/admin-guide-cloud/telemetry-alarms.html

[venkatamahesh (venkatamaheshkotha)]

This affects table also and is updated in config-reference rst version:

https://github.com/openstack/openstack-manuals/blob/master/doc/config-reference/source/tables/aodh-common.rst

[Lana (loquacity)]

I think the documentation has been picked up by the Config Ref adequately: https://docs.openstack.org/ocata/config-reference/telemetry/alarming-config-options.html

The Telemetry Alarms section in the Admin Guide doesn't need to document this further than it already has, IMHO.