Added a nodump to chapter05/introduction - we don't need to automate the 'echo $LFS'

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@7096 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter05/introduction.xml

@@ -56,7 +56,7 @@ these reminders.</para></important>
 <para>Check one last time that the <envar>LFS</envar> environment 
 variable is set up properly:</para>
 
-<screen><userinput>echo $LFS</userinput></screen>
+<screen role="nodump"><userinput>echo $LFS</userinput></screen>
 
 <para>Make sure the output shows the path to the LFS partition's mount
 point, which is <filename class="directory">/mnt/lfs</filename>, using