[1.8.x] Corrected doc'd differences between django-admin and manage.py.

Backport of 8091e8c5 from master

docs/ref/django-admin.txt

@@ -11,20 +11,14 @@ This document outlines all it can do.
     ``django-admin.py``.
 
 In addition, ``manage.py`` is automatically created in each Django project.
-``manage.py`` is a thin wrapper around ``django-admin`` that takes care of
-several things for you before delegating to ``django-admin``:
+``manage.py`` does the same thing as ``django-admin`` but takes care of a few
+things for you:
 
 * It puts your project's package on ``sys.path``.
 
 * It sets the :envvar:`DJANGO_SETTINGS_MODULE` environment variable so that
   it points to your project's ``settings.py`` file.
 
-* It calls :func:`django.setup()` to initialize various internals of Django.
-
-.. versionadded:: 1.7
-
-    :func:`django.setup()` didn't exist in previous versions of Django.
-
 The ``django-admin`` script should be on your system path if you installed
 Django via its ``setup.py`` utility. If it's not on your path, you can find it
 in ``site-packages/django/bin`` within your Python installation. Consider