chg: use --daemon-postexec chdir:/ instead of --cwd /

The chgserver is designed to load repo config from current directory. "--cwd /"
will prevent chgserver from loading repo config and generate a wrong
confighash, which will result in a redirect loop. This patch removes "--cwd /"
and uses "--daemon-postexec chdir:/" instead.

contrib/chg/chg.c

@@ -211,10 +211,9 b' static void execcmdserver(const struct c'
 	const char *baseargv[] = {
 		hgcmd,
 		"serve",
-		"--cwd", "/",
 		"--cmdserver", "chgunix",
 		"--address", opts->sockname,
-		"--daemon-postexec", "none",
+		"--daemon-postexec", "chdir:/",
 		"--pid-file", opts->pidfile,
 		"--config", "extensions.chgserver=",
 	};