Finish adding help strings to all options

[Kyle Mestery]

Bug 1094989 addressed adding help strings to common quantum configuration options. But each agent also has it's own set of configuration options. This bug addresses those as well.

The following files need to have help strings added:

quantum/agent/l3_agent.py
quantum/agent/netns_cleanup_util.py
quantum/agent/dhcp_agent.py
quantum/agent/metadata/agent.py
quantum/debug/debug_agent.py
quantum/plugins/metaplugin/common/config.py
quantum/plugins/bigswitch/plugin.py
quantum/plugins/linuxbridge/common/config.py
quantum/plugins/nec/common/config.py
quantum/plugins/nicira/nicira_nvp_plugin/common/config.py
quantum/plugins/ryu/common/config.py
quantum/plugins/openvswitch/common/config.py
quantum/plugins/hyperv/agent/hyperv_quantum_agent.py

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/20618

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/20618
Committed: http://github.com/openstack/quantum/commit/041e2f75e7f82b0841e38baded9628aa44d81f87
Submitter: Jenkins
Branch: master

commit 041e2f75e7f82b0841e38baded9628aa44d81f87
Author: Kyle Mestery <email address hidden>
Date: Mon Jan 28 10:18:32 2013 +0000

    Finish adding help strings to all config options in Quantum code.

    This adds reasonable help strings to all remaining config options
    in Quantum code. This includes all the plugins as well.

    Fixes bug 1101356

    Change-Id: I1cbe8303ad6d86756b992ae302707a0365625f52