Adding nodump to two commands in chapter 3 introduction - they are out of place and used more as explanatory text.

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@6825 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter03/introduction.xml

@@ -35,7 +35,7 @@ of the building process.</para>
 <emphasis>root</emphasis>, the following command before starting the
 download session:</para>
 
-<screen><userinput>mkdir $LFS/sources</userinput></screen>
+<screen role="nodump"><userinput>mkdir $LFS/sources</userinput></screen>
 
 <para>Make this directory writable and sticky. <quote>Sticky</quote>
 means that even if multiple users have write permission on a
@@ -43,7 +43,7 @@ directory, only the owner of a file can delete the file within a
 sticky directory. The following command will enable the write and
 sticky modes:</para>
 
-<screen><userinput>chmod a+wt $LFS/sources</userinput></screen>
+<screen role="nodump"><userinput>chmod a+wt $LFS/sources</userinput></screen>
 
 </sect1>