Removed superfulous definitions of Object#singleton_class

MRI implemented it in 1.9.2 already.

Author: mvidner

lib/dbus/proxy_object.rb

@@ -144,10 +144,5 @@ def method_missing(name, *args, &reply_handler)
         raise NoMethodError, "undefined method `#{name}' for DBus interface `#{@default_iface}' on object `#{@path}'"
       end
     end
-
-    # Returns the singleton class of the object.
-    def singleton_class
-      (class << self ; self ; end)
-    end
   end # class ProxyObject
 end

lib/dbus/proxy_object_interface.rb

@@ -34,11 +34,6 @@ def to_str
       @name
     end
 
-    # Returns the singleton class of the interface.
-    def singleton_class
-      (class << self ; self ; end)
-    end
-
     # Defines a method on the interface from the Method descriptor _m_.
     def define_method_from_descriptor(m)
       m.params.each do |fpar|