fix false positive in signal5.tests

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/shell/ash_test/ash-signals/signal5.tests b/shell/ash_test/ash-signals/signal5.tests
index 5003180..371120e 100755
--- a/shell/ash_test/ash-signals/signal5.tests
+++ b/shell/ash_test/ash-signals/signal5.tests
@@ -5,8 +5,9 @@
     echo "$1 sec passed, sending USR1 to parent"
     kill -USR1 $$
 }
+stub 3 &
 stub 2 &
-stub 1 &
+sleep 1
 until { echo "Waiting"; wait; } do
     echo "Wait exit code: $?"
 done