(handler): When exitting upon an abnormal signal, yppush_exit() should not

attempt to clear its pending jobs list, as this could trigger another
signal, and cause an infinite recursion. What yppush_exit() tests
in order to determine whether to flush pending jobs is the
yppush_joblist chained list, so this is what needs to be cleared
in that case (not the yppush_jobs counter).

Reviewed by:	audit@ (no objection)
MFC after:	2 weeks

usr.sbin/yppush/yppush_main.c

@@ -208,7 +208,7 @@ static void
 handler(int sig)
 {
 	if (sig == SIGTERM || sig == SIGINT || sig == SIGABRT) {
-		yppush_jobs = 0;
+		yppush_joblist = NULL;
 		yppush_exit(1);
 	}