modify description of "Inject guest networking config"
modify description of "Inject guest networking config"

The description of "Inject guest networking config" in
support-matrix is misleading. Correct it.
In fact, If we config static ip,
guest os can not access metadata service to get ip config.
Closes-Bug: #1612913

Change-Id: I1892e5273a77516dd8e1525e6064fb95fa65e4d3

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