Update zlib URL.

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@2233 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

appendixa/zlib-down.xml

@@ -2,5 +2,5 @@
 <title>Official Download Location</title>
 
 <para><literallayout>Zlib (&zlib-version;):
-<ulink url="ftp://ftp.info-zip.org/pub/infozip/zlib/"/></literallayout></para>
+<ulink url="http://www.gzip.org/zlib/"/></literallayout></para>
 </sect2>