[PATCH STABLE] test-push-http: do not clear pid file

[Yuya Nishihara]

On Fri, 27 Apr 2018 21:49:33 -0400, Matt Harbison wrote:
> I also wonder, given the persistent nagging address in use failure on  
> Windows when relaunching `hg serve` in some tests, if we should just have  
> some way of sending an exit command over the socket, so that it can  
> shutdown gracefully.  Obviously, it would have to be a test extension.

I can upstream the win32ill extension, which makes hg listen to WM_CLOSE,
but I have no idea if it works well with the win32.setsignalhandler() hack.

https://bitbucket.org/tortoisehg/thg/src/tip/tortoisehg/util/win32ill.py