[1.2.X] Advises that the Ubuntu package manager drops the .py extension from...

[1.2.X] Advises that the Ubuntu package manager drops the .py extension from django-admin.py. Thanks to islands for the report and d0ugal for the patch.

Backport of [14108] from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@14109 bcc190cf-cafb-0310-a4f2-bffc1f526a37