typo

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@11539 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter07/systemd-custom.xml

@@ -60,7 +60,7 @@ EOF</userinput></screen>
     <warning>
       <para>
         Do not create the symbolic link above if a separate partition is used
-        for <filename class="directory">/tmp</filename>.  This will prvent the
+        for <filename class="directory">/tmp</filename>.  This will prevent the
         root file system (/) from being remounted r/w and make the system
         unusable when booted.
       </para>