Smart pointer to %ignored class doesn't expose inherited methods fix.

Regression introduced in swig-3.0.9 by 3efdbc8
Closes #690

Examples/test-suite/smart_pointer_ignore.i

@@ -0,0 +1,33 @@
+%module smart_pointer_ignore
+
+
+%ignore Derived;
+
+%inline %{
+class Base {
+  public:
+    void base() {}
+};
+
+class Derived : public Base {
+  public:
+    void derived() {}
+};
+
+template <class T>
+class Ptr {
+public:
+  Ptr(T *t) : ptr(t) {}
+  T * operator->() const { return ptr; }
+private:
+  T *ptr;
+};
+%}
+
+%template(DerivedPtr) Ptr<Derived>;
+
+%inline %{
+Ptr<Derived> makeDerived() {
+  return Ptr<Derived>(new Derived());
+}
+%}