secret's user_meta quota can not be configured

[Eric Xie]

1. Env
stable/mitaka

2. Issue
In https://github.com/openstack/barbican-specs/blob/master/specs/mitaka/add-user-metadata.rst#data-model-impact:
"A limit must also be set as to how much meta-data a user can add to a secret. quota_secret_meta will be added to the Barbican config and set to -1, which allows for unlimited metadata."

But there was no configuration for quota_secret_meta in etc/barbican/barbican.conf.

Expect:
     Some like 'quota_secret_meta' should be added in etc/barbican/barbican.conf.

[Fernando Diaz (diazjf)]

In Progress: https://review.openstack.org/#/c/294274/

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/313788

[OpenStack Infra (hudson-openstack)]

Change abandoned by Fernando Diaz (<email address hidden>) on branch: master
Review: https://review.openstack.org/313788
Reason: Will revisit in Pike.

[Grzegorz Grasza (xek)]

Closing out bugs created before migration to StoryBoard. Please re-open if you are of the opinion it is still current.