Prevent people from using "startapp" to create apps with the same name as...

Prevent people from using "startapp" to create apps with the same name as their project. Might stop some of the accidents.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@2946 bcc190cf-cafb-0310-a4f2-bffc1f526a37