Fixed #17503 -- A destination directory passed to startproject or startapp as...

Fixed #17503 -- A destination directory passed to startproject or startapp as optional second argument is now reused as the project/app directory, rather than a new project/app directory created within it. Refs #17042.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@17340 bcc190cf-cafb-0310-a4f2-bffc1f526a37