metering-agent sync useless meter label cause error

[Zhengwei Gao]

Metering-agent may be retrieve useless meter label by sync_routers_task, which tenant's router related metering label didn't scheduler to metering-agent's host. When neutron deployed multi-network node, it will cause Error, e.g Stderr: 'Cannot open network namespace: No such file or directory\n' execute /usr/lib/python2.7/dist-packages/neutron/agent/linux/utils.py:60

[James Page (james-page)]

Hooking up Ubuntu bug with Neutron work to resolve this under:

  https://review.openstack.org/#/c/361023/

[OpenStack Infra (hudson-openstack)]

Change abandoned by Armando Migliaccio (<email address hidden>) on branch: master
Review: https://review.openstack.org/361023
Reason: This review is > 4 weeks without comment, and failed Jenkins the last time it was checked. We are abandoning this for now. Feel free to reactivate the review by pressing the restore button and leaving a 'recheck' comment to get fresh test results.

[Brian Haley (brian-haley)]

Looks like this is a duplicate, so fix should be in anything Queens or later, let me link it.