ash: add another ${v/a/b} test we currently fail

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
diff --git a/shell/ash_test/ash-vars/var_bash5.right b/shell/ash_test/ash-vars/var_bash5.right
new file mode 100644
index 0000000..278ed32
--- /dev/null
+++ b/shell/ash_test/ash-vars/var_bash5.right
@@ -0,0 +1,4 @@
+a/
+a/d
+a/e/f
+Done: 0