docs: autoupdater: remove parts only relevant for Gluon versions before v2014.3

docs/features/autoupdater.rst

@@ -34,7 +34,6 @@ A fully automated nightly build could use the following commands:
 
     rm -rf /where/to/put/this/experimental
     cp -r images /where/to/put/this/experimental
-    ln -s experimental.manifest /where/to/put/this/experimental/sysupgrade/manifest
 
 
 Infrastructure
@@ -55,10 +54,6 @@ We suggest to have following directory tree accessible via http:
                     sysupgrade/
                     factory/
 
-The last level is generated by the Gluon build process. Do not forget
-to create symlinks from ``manifest`` to ``<branch>.manifest`` in the
-sysupgrade directories to allow upgrades from Gluon versions before 2014.3.
-
 The server should be available via IPv6.
 
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