Removed ridiculous extra space around the title in docs/topics/db/aggregation.txt

git-svn-id: http://code.djangoproject.com/svn/django/trunk@12121 bcc190cf-cafb-0310-a4f2-bffc1f526a37

docs/topics/db/aggregation.txt

@@ -1,8 +1,8 @@
 .. _topics-db-aggregation:
 
-=============
- Aggregation
-=============
+===========
+Aggregation
+===========
 
 .. versionadded:: 1.1