[system-administrators-guide] Added the NetworkManager chapter to the preface.

[jhradile]

commit b64281b99642f3f036f330c0f45293999ed53c15
Author: Jaromir Hradilek <jhradilek at redhat.com>
Date:   Mon Jul 1 14:50:50 2013 +0200

    Added the NetworkManager chapter to the preface.

 en-US/Preface.xml |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)
---
diff --git a/en-US/Preface.xml b/en-US/Preface.xml
index 9eb64a3..25f1d90 100644
--- a/en-US/Preface.xml
+++ b/en-US/Preface.xml
@@ -89,11 +89,9 @@
           <para>
             This part describes how to configure the network on &MAJOROS;.
           </para>
-          <!-- jhradilek: TBD F15: Uncomment this as soon as the NetworkManager chapter is updated.
           <para>
             <xref linkend="ch-NetworkManager" /> focuses on <application>NetworkManager</application>, a dynamic network control and configuration system that attempts to keep network devices and connections up and active when they are available. Read this chapter for information how to run the <systemitem class="service">NetworkManager</systemitem> daemon, and how to interact with it using the corresponding applet for the notification area.
           </para>
-          -->
           <para>
             <xref linkend="ch-Network_Interfaces" /> explores various interface configuration files, interface control scripts, and network function files located in the <filename class="directory">/etc/sysconfig/network-scripts/</filename> directory. Read this chapter for information how to use these files to configure network interfaces.
           </para>