Fix for issue #585 - RESTEasy SpringBeanProcessor cannot support factory bean's factory method

This fixes the problem with certain factory methods (eg. https://github.com/resteasy/Resteasy/issues/585).
Not all factory methodes implement a method called "getX" (which is what the code above expect)
and instead make one or more methods called getObject, which either return Object.class or a more specific class.
           
 The code added here adds this check and fixes this issue in version 2.3.5.