Fix 404 for latest 1.4.x-stable release signature

Using an archive instead of a distribution package as explained in
0fd20da

Author: carenas

index.html

@@ -163,7 +163,7 @@ <h3>Download&ndash;Stable releases</h3>
        <li>and more...
       </ul>
 
-	<li><a href="https://github.com/libevent/libevent/archive/release-1.4.15-stable.tar.gz">libevent-1.4.15-stable.tar.gz</a> [<a href="https://github.com/downloads/libevent/libevent/libevent-1.4.15-stable.tar.gz.sig">GPG Sig</a>] <a href="https://raw.github.com/libevent/libevent/release-1.4.15-stable/ChangeLog">ChangeLog</a><br>Released 2015-01-05
+	<li><a href="https://github.com/libevent/libevent/archive/release-1.4.15-stable.tar.gz">libevent-1.4.15-stable.tar.gz</a> <a href="https://raw.github.com/libevent/libevent/release-1.4.15-stable/ChangeLog">ChangeLog</a><br>Released 2015-01-05
           <ul>
             <li>Changelog to follow
            </ul>