No way to allow exceptions to raise out of Django

[ianb@…]

In trunk, django.core.handlers.base, exceptions are captured and displayed. However, in testing environments it is preferable that the exception not be handled and simply raised (or, for example, a rollback and then the exception is re-raised). There's no way to get it to do this now.

This also allows Django to use Paste's exception handlers. Paste in particular indicates this by putting environ['paste.throw_errors']=True into the WSGI environment, and does this both when an exception handler is already installed, and in testing environments.

[Michael Radziej <mir@…>]

duplicate of #3452