[1.2.X] Fixed #14863 - Add contrib.messages to list of default INSTAL…

…LED_APPS in tutorial.

Backport of r14870 (without staticfiles) from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@14871 bcc190cf-cafb-0310-a4f2-bffc1f526a37

docs/intro/tutorial01.txt

@@ -225,6 +225,8 @@ come with Django:
     * :mod:`django.contrib.sites` -- A framework for managing multiple sites
       with one Django installation.
 
+    * :mod:`django.contrib.messages` -- A messaging framework.
+
 These applications are included by default as a convenience for the common case.
 
 Each of these applications makes use of at least one database table, though,