Improve the help text for the network options (4)
Improve the help text for the network options (4)

The previous commit moved all the options from nova/network/manager.py
to a central location in nova/conf/network.py. This commit adds
additional help text to those options. Because of the large number of
options, the improved help text will be split into several patches; this
is patch 4 of 4.

Blueprint centralize-config-options-newton

Change-Id: I06d9a76afe6a926db5f3f689b212f2562dbb6a92

mikalstill/nova,klmitch/nova,phenoxim/nova,sebrandon1/nova,Juniper/nova,jianghuaw/nova,alaski/nova,phenoxim/nova,klmitch/nova,sebrandon1/nova,gooddata/openstack-nova,cloudbase/nova,mahak/nova,rajalokan/nova,gooddata/openstack-nova,cloudbase/nova,hanlind/nova,rajalokan/nova,mikalstill/nova,cloudbase/nova,rahulunair/nova,jianghuaw/nova,Juniper/nova,klmitch/nova,hanlind/nova,sebrandon1/nova,Juniper/nova,mikalstill/nova,hanlind/nova,openstack/nova,gooddata/openstack-nova,alaski/nova,rahulunair/nova,vmturbo/nova,vmturbo/nova,mahak/nova,jianghuaw/nova,vmturbo/nova,rahulunair/nova,openstack/nova,openstack/nova,klmitch/nova,rajalokan/nova,vmturbo/nova,mahak/nova,Juniper/nova,jianghuaw/nova,rajalokan/nova,gooddata/openstack-nova