added /etc/sysconfig/rc update (include network_devices variable)

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@1449 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter07/network.xml

@@ -36,6 +36,14 @@ network interface name (such as eth0 or eth0:1)</para>
 
 <para><screen><userinput>mkdir /etc/sysconfig/network-devices</userinput></screen></para>
 
+<para>We also need to add this directory path to the /etc/sysconfig/rc file
+so that other scripts (like ifup and ifdown) know where this directory is
+located.</para>
+
+<para>Update the /etc/sysconfig/rc file by running:</para>
+
+<para><screen><userinput>echo "network_devices=/etc/sysconfig/network-devices" >> /etc/sysconfig/rc</userinput></screen></para>
+
 <para>Now, new files are created in that directory containing the following.
 The following command creates a sample ifconfig.eth0 file:</para>