Remove openstack network section from overview

This section is old and doesn't make much sense
anymore, let's remove it. Neutron is already mentioned
as a default service and has its own config guide.

TrivialFix

Change-Id: I2a2ed574f9eca7b87fb9bb6422568ed4fc55f057

Author: brianphaley

doc/source/overview.rst

@@ -52,12 +52,6 @@ Web Server
 
 -  Apache
 
-OpenStack Network
------------------
-
--  Neutron: A basic configuration approximating the original FlatDHCP
-   mode using OpenVSwitch.
-
 Services
 --------