win32: drop a py26 daemonizing hack
I'm not sure what the referenced hang specifically was, but the whole test suite
(with #serve) still runs on python 2.7.13. Aside from no longer prepending
"cmd.exe /c", this backs out
ca6aa8362f33.
I'm trying to track down a rare failure of TerminateProcess() with an access
error, and I've seen random extra python processes hanging around after running
tests sometimes, so this might help.
However,
e48cb1c7a902 forces this change. Since the pid object is no longer
converted to a string, the cmd.exe pid was being saved instead of the hg pid,
and none of the daemons were being killed.