glib2: avoid stack overflow
glib2: avoid stack overflow

It's caused when both parent class and sub class define deprecated
method of the same method.

The following code reproduces the following case:

    class A
      def initialize
        p [A, __method__]
      end

      alias_method :initialize_x, :initialize
      def initialize
        p [A, __method__]
        initialize_x
      end
    end

    class B < A
      alias_method :initialize_x, :initialize
      def initialize
        p [B, __method__]
        initialize_x
      end
    end

    B.new
    # => [B, :initialize]
    # => [A, :initialize]
    # => [A, :initialize]
    # => ...
    # => stack level too deep

kitachro/ruby-gnome2,kitachro/ruby-gnome2,kitachro/ruby-gnome2,kitachro/ruby-gnome2,kitachro/ruby-gnome2