Fix wrong namespace of test classes

    class NewClass < OSX::NSObject
    end
    obj = NewClass.new # OK
    obj = OSX::NewClass.new # should be an error

git-svn-id: https://svn.code.sf.net/p/rubycocoa/svn/trunk/src@2519 f4f36d40-9719-0410-9868-dde021a23eda