No longer capture decideHTTP errors

One more.... :D 
Now this one changes the behavior a bit (for the better I hope). 

For some context on what is happening, I'm getting intermittent exceptions of `UnboundLocalError: local variable 'decision' referenced before assignment` and looking over it, the only way this can happen is if `decideICAP` raises an exception that was then caught and printed then tries to return `decision`. And so I wondered what the original exception was. A bit of judicial debugging shows `e` is `AttributeError("'HTTP' object has no attribute 'upgrade'",)`. 

So seeing how an exception in decideHTTP will still raise an exception, it makes sense to let the original one bubble up.