Bugfix: p.h.HTTPException.__str __

[digitalresistor]

There are those crazies among us* that use something like the following:

raise HTTPBadRequest({'error': 'Invalid something or other'})

This blew up when attempting to call str() on the resulting object due to __str__ returning self.detail directly.

This fixes this and lets those crazies continue on with their craziness.

• Me, I am that crazy person, because it makes things like this simple:

@view_config(
    accept='application/json',
    renderer='json',
    context=HTTPException,
    )
def reterror(context, request):
    try:
        if not context.detail:
            raise ValueError('Missing detail in context')
        context.json_body = context.detail
    except:
        context.json_body = {'error': 'Unknown error has occured.'}

    return context