Duplication of resources with discovery extension loaded for source with multiple sinks

[Eoghan Glynn]

Where a single source has a pluggable discovery extension loaded and is associated with multiple sinks, the discovered resources are duplicated for each sink.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/112980

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/112980
Committed: https://git.openstack.org/cgit/openstack/ceilometer/commit/?id=2bc48ff261c5d78a1d3dab884337dc08fc1a4aa4
Submitter: Jenkins
Branch: master

commit 2bc48ff261c5d78a1d3dab884337dc08fc1a4aa4
Author: Eoghan Glynn <email address hidden>
Date: Fri Aug 8 18:27:53 2014 +0100

    Avoid duplication of discovery for multi-sink sources

    Perviously, where a single source has a pluggable discovery
    extension loaded and is associated with multiple sinks, the
    discovered resources were duplicated for each sink.

    Now, we ensure that duplicate discovery extensions are
    excluded.

    Change-Id: Icffcc65f2be2baef7730b31773b39ffdda0454a7
    Closes-Bug: #1354536