added a note that the downloaded tarball should be kept

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@1968 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter02/install.xml

@@ -71,7 +71,8 @@ after you enter the chroot'ed environment. Even running something like
 tree.</para>
 
 <para>So, save yourself a lot of hassle and just remove the source directory
-immediately after you have installed it.</para>
+immediately after you have installed it, but keep the downloaded tarball
+available for when you need it again.</para>
 
 <para>There is one exception; the kernel source tree. Keep it around as you
 will need it later in this book when building a kernel. Nothing will use