Revert "Suppress section edit links with action=render"

This reverts commit 2248021997324c8694430a3c010b8b81482be0c3.

That revision caused section edit links to be shown on views of old
revisions. See comments there for suggestions on reimplementing it.

Change-Id: Ie65e3de84b44866e4ab1fc222a365cb3a9180ee1