Modify the link to make more direct and clear
Modify the link to make more direct and clear

There should provide link for 'command-line interface for networking',
but the article provide the link for 'OpenStack End User Guide', so it
is not direct and accurate, so this patch provide the direct link and
delete the useless link.

Change-Id: Ic023b4feb3de076d4e17e80e57dfa01b1362864c

openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals