Fix Java swigReleaseOwnership() and swigTakeOwnership() regression

Fixes segfault when using non-director classes.
Restores a dynamic_cast which was previously removed.
The dynamic_cast is not needed for the swig_connect_director call ...
we'll have to find another solution for #449 for Java.

Closes #1184

Examples/test-suite/director_ownership.i

@@ -0,0 +1,72 @@
+%module(directors="1") director_ownership
+
+// Github issue #1184
+
+%include "std_string.i"
+
+%feature("director") example::ContentBase;
+%feature("director") example::ContentDerived;
+
+%newobject example::make_content;
+
+%inline %{
+#include <string>
+
+namespace example
+{
+
+class ContentBase
+{
+public:
+    ContentBase() {}
+    virtual ~ContentBase() {}
+    virtual std::string get_name() const = 0;
+};
+
+
+class ContentDerived: public ContentBase
+{
+public:
+    ContentDerived():ContentBase() { m_name = "ContentDerived"; }
+    virtual ~ContentDerived() {}
+    virtual std::string get_name() const override { return m_name; }
+
+private:
+    std::string m_name;
+};
+
+
+class Container
+{
+public:
+    Container() { m_content = 0; }
+    ~Container()
+    {
+        clear_content();
+    }
+    // the container takes the ownership of the content
+    void set_content(ContentBase* content)
+    {
+        clear_content();
+        m_content = content;
+    }
+    ContentBase* get_content() { return m_content; }
+
+private:
+    void clear_content()
+    {
+        if(m_content)
+        {
+            delete m_content;
+            m_content = 0;
+        }
+    }
+    
+private:
+    ContentBase* m_content;
+};
+
+static ContentBase* make_content() { return new ContentDerived(); }
+
+} // namespace example
+%}