Added a note to the lockin tests stating that blank output is bad

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@2941 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter05/lockingglibc.xml

@@ -60,7 +60,8 @@ output of the last command will be:</para>
 <blockquote><screen>[Requesting program interpreter: /tools/lib/ld-linux.so.2]</screen></blockquote>
 
 <para>If you did not receive the output as shown above, then something is
-seriously wrong. You will need to investigate and retrace your steps to find
+seriously wrong. This includes if the output of the command is blank!
+You will need to investigate and retrace your steps to find
 out where the problem is and correct it. There is no point in continuing
 until this is done. Most likely something went wrong with the specs file
 amendment above. Note especially that <filename>/tools/lib</filename> appears

chapter06/adjustingtoolchain.xml

@@ -70,7 +70,8 @@ output of the last command will be:</para>
 <blockquote><screen>[Requesting program interpreter: /lib/ld-linux.so.2]</screen></blockquote>
 
 <para>If you did not receive the output as shown above, then something is
-seriously wrong. You will need to investigate and retrace your steps to find
+seriously wrong. This includes the output of the above command being empty!
+You will need to investigate and retrace your steps to find
 out where the problem is and correct it. There is no point in continuing
 until this is done. Most likely something went wrong with the specs file
 amendment above. Note especially that <filename>/lib</filename> now appears as