We should branch after the first beta.

We did this for 1.6 and it was very effective. 95%+ of fixes which merge
during the alpha are backported, as the policy is "all but really major
features". It's easier to just not merge any really major features.
After beta, we have feature freeze so we need to backport bugs to stable
but not features, so then the branch makes sense.

docs/internals/howto-release-django.txt

@@ -329,7 +329,7 @@ You're almost done! All that's left to do now is:
    example, after releasing 1.5.1, update ``VERSION`` to
    ``VERSION = (1, 5, 2, 'alpha', 0)``.
 
-#. For the first alpha release of a new version (when we create the
+#. For the first beta release of a new version (when we create the
    ``stable/1.?.x`` git branch), you'll want to create a new
    ``DocumentRelease`` object in the ``docs.djangoproject.com`` database for
    the new version's docs, and update the ``docs/fixtures/doc_releases.json``
@@ -340,11 +340,11 @@ You're almost done! All that's left to do now is:
    default if it's a final release). Not all versions are declared;
    take example on previous releases.
 
-.. _Trac's versions list: https://code.djangoproject.com/admin/ticket/versions
-
 #. On the master branch, remove the ``UNDER DEVELOPMENT`` header in the notes
    of the release that's just been pushed out.
 
+.. _Trac's versions list: https://code.djangoproject.com/admin/ticket/versions
+
 Notes on setting the VERSION tuple
 ==================================