Possible bug and solution in OGL

I think I've found a bug (and also a workaround) in OGL, but I've
never submitted a patch before, so I'm not sure of how to do it.

Bug:
Create two shapes. Connect them with a line. Call line.Delete().
Everything seems ok but... Try to drag any of the two shapes. You get
AttributeError: 'NoneType' object has no attribute 'OnErase'.

Patch:
On file \wx\lib\ogl\_lines.py add a method to class LineShape to
override the inherited Delete method:

    def Delete(self):
        self.Unlink()
        Shape.Delete(self)

Any comments on the workaround?