hush: fix "redirects can close script fd" bug

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/shell/hush_test/hush-misc/redir_script.right b/shell/hush_test/hush-misc/redir_script.right
new file mode 100644
index 0000000..6694ed3
--- /dev/null
+++ b/shell/hush_test/hush-misc/redir_script.right
@@ -0,0 +1 @@
+Ok: script fd is not closed