Simplify, drop SYNC_SHUTDOWN state file, not needed anymore

Similar to 6224166 (previous commit), this old code is a remnant of a
bygone era and not needed anymore.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

src/sig.c

@@ -209,8 +209,6 @@ void do_kill(int signo)
 
 void do_shutdown(shutop_t op)
 {
-	touch(SYNC_SHUTDOWN);
-
 	if (sdown)
 		run_interactive(sdown, "Calling shutdown hook: %s", sdown);
 
@@ -501,9 +499,6 @@ void sig_setup(uev_ctx_t *ctx)
 
 	_d("Setup signals");
 
-	/* Cleanup any stale finit control files */
-	erase(SYNC_SHUTDOWN);
-
 	/*
 	 * Standard SysV init calls ctrl-alt-delete handler
 	 * We need to disable kernel default so it sends us SIGINT