Provide cfg to ignore lvm descriptor leak warnings

[OpenStack Infra]

https://review.openstack.org/378013
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commit 844aa0ac3e8068e25193a680ac0c63d68682de4b
Author: John Griffith <email address hidden>
Date: Fri Sep 2 23:00:32 2016 +0000

    Provide cfg to ignore lvm descriptor leak warnings

    For some reason the leaded descriptor warning message coming
    from LVM is causing Cinder to fail startup and it appears to be
    masking out the vg response in vgs calls.

    We typically don't hit this, but due to the nature of Kolla and
    I guess going through the different processes via the containers
    this gets logged every time vgs is called. Eric Harney rightly
    pointed out that rather than use exception handling and such
    that we should use the LVM env variable mechanism we already have
    in place in Cinder.

    For now this patch added a new config option to the LVM driver:
        lvm_suppress_fd_warnings=True|False

    This is useful for K8 deployments that have an indirect call to the
    LVM cmds which results in failures.

    For those that are interested, this can also be done outside of
    cinder by setting the silence_logs variable in lvm.conf

    This is made optional as a config flag to avoid any breakage for
    existing deployments during upgrade.

    DocImpact: Need to add info regarding config update to docs

    Change-Id: I85612fa49475beea58d30330c8fe8352a2f91123
    Closes-Bug: #1619701
    (cherry picked from commit 055ec1ce73ca55c463481c349b42dee66e5e86d6)

[Sean McGinnis (sean-mcginnis)]

John, is there anything besides the automatically generated config tables and sample cinder.conf that should be added to the docs explaining what this is used for? If not, we can just close out this bug as invalid.

[Sean McGinnis (sean-mcginnis)]

Unassigning due to no activity for > 6 months.

[Jay Bryant (jsbryant)]

Now that we are automatically generating configs we should be good here.