Update the links to api-ref of network

Follow this patchset, I found more link to be updated:
https://review.openstack.org/#/c/349124/

This patch updates the links of networks_client. I have the same
idea as Masayuki Igawa, hope that we have a tool to update the
link.

Change-Id: I917b6c06b7fd502865c19dbdb6fd8535303c1fe8
2 files changed