Fix a bug which caused proxy corruption with setters.
Fix a bug which caused proxy corruption with setters.

Do not override the TiObject* of a JavaScript proxy object.
This was leading to the proxy becoming un-usable since it
no longer pointed to a valid TiObject* instance.

appcelerator/titanium_mobile_blackberry,appcelerator/titanium_mobile_blackberry,appcelerator/titanium_mobile_blackberry,appcelerator/titanium_mobile_blackberry,appcelerator/titanium_mobile_blackberry,appcelerator/titanium_mobile_blackberry