website: Get rid of some quite old branches.

RHEL 7.3 will have 1.32.6, so we should encourage people to move to at
least that version for recent features.

Fixes commit f4e4a66.

website/index.html.in

@@ -189,15 +189,6 @@ LATEST-VERSION: @PACKAGE_VERSION@
   <strong>
   <a href="download/1.34-stable/">1.34.x</a>,
   <a href="download/1.32-stable/">1.32.x</a>,
-  <a href="download/1.30-stable/">1.30.x</a>,
-  </strong>
-  Old stable:
-  <strong>
-  <a href="download/1.28-stable/">1.28.x</a>,
-  <a href="download/1.26-stable/">1.26.x</a>,
-  <a href="download/1.24-stable/">1.24.x</a>,
-  <a href="download/1.22-stable/">1.22.x</a>,
-  <a href="download/1.20-stable/">1.20.x</a>
   </strong>
 </small></em>
 </p>