[PATCH 2 of 2 V2] dispatch: flush ui before returning from _runcatch

[Jun Wu]

On 03/14/2016 03:09 PM, Yuya Nishihara wrote:
> I guess this wouldn't catch the all cases. I'll recheck it tomorrow.

No, it wouldn't. Namely ParseError has "return -1" (which I think can be
removed) and re-raise.

I didn't put it in "finally" because the inner try block has a "finally" 
already. I think it may be better to do "ui.flush()" only once.

Now I prefer adding a "finally" here.