Fixed #25153 -- Moved 'polls' first in tutorial's INSTALLED_APPS.

docs/intro/tutorial02.txt

@@ -206,13 +206,13 @@ look like this:
     :filename: mysite/settings.py
 
     INSTALLED_APPS = [
+        'polls',
         'django.contrib.admin',
         'django.contrib.auth',
         'django.contrib.contenttypes',
         'django.contrib.sessions',
         'django.contrib.messages',
         'django.contrib.staticfiles',
-        'polls',
     ]
 
 Now Django knows to include the ``polls`` app. Let's run another command: