BaseSubprocessTransport._kill_wait() now also call close()
BaseSubprocessTransport._kill_wait() now also call close()

close() closes pipes, which is not None yet by _kill_wait().

fallen/asyncio,fallen/asyncio,gvanrossum/asyncio,Martiusweb/asyncio,fallen/asyncio,vxgmichel/asyncio,manipopopo/asyncio,ajdavis/asyncio,gsb-eng/asyncio,vxgmichel/asyncio,ajdavis/asyncio,1st1/asyncio,gsb-eng/asyncio,ajdavis/asyncio,Martiusweb/asyncio,manipopopo/asyncio,1st1/asyncio,vxgmichel/asyncio,haypo/trollius,jashandeep-sohi/asyncio,manipopopo/asyncio,haypo/trollius,1st1/asyncio,Martiusweb/asyncio,gsb-eng/asyncio,gvanrossum/asyncio,haypo/trollius,jashandeep-sohi/asyncio,jashandeep-sohi/asyncio,gvanrossum/asyncio