iproute_arg_supported in neutron/agent/linux/ip_lib.py causes error logs when they should be debug

[Matthew Thode]

this function calls help. calling help typically causes the program being called to exit non-zero. This causes the command to be logged as an error even though it should not be.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/180709

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/180709
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=dd9129d42cf280458301d5101a131c4c5c12abdf
Submitter: Jenkins
Branch: master

commit dd9129d42cf280458301d5101a131c4c5c12abdf
Author: Matthew Thode <email address hidden>
Date: Wed May 6 14:39:20 2015 -0500

    changes log level to debug for help calls

    Calling help typically causes the program being called to exit non-zero.
    This causes the command to be logged as an error even though it should not be.
    By setting 'log_fail_as_error=False' we log to debug. This helps clean
    up logs.

    Change-Id: I13f9488b9bc524bb85047e9b2dcf4e8a76bd6c11
    Closes-Bug: 1452425

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: neutron-pecan
Review: https://review.openstack.org/185072