Removing Line2D is broken

[WeatherGod]

I have been trying out all of my code examples from my book against master to find any additional bugs. I came across this one in chapter 2 where I set up an example for selecting and removing Line2D objects from a plot. Doing so now causes this traceback:

ben@tigger:~/Documents/InteractiveMPL$ python chp2/track_deleter.py 
Traceback (most recent call last):
  File "/home/ben/miniconda/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-linux-x86_64.egg/matplotlib/backends/backend_qt5.py", line 314, in keyPressEvent
    FigureCanvasBase.key_press_event(self, key, guiEvent=event)
  File "/home/ben/miniconda/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-linux-x86_64.egg/matplotlib/backend_bases.py", line 1846, in key_press_event
    self.callbacks.process(s, event)
  File "/home/ben/miniconda/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-linux-x86_64.egg/matplotlib/cbook.py", line 562, in process
    proxy(*args, **kwargs)
  File "/home/ben/miniconda/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-linux-x86_64.egg/matplotlib/cbook.py", line 429, in __call__
    return mtd(*args, **kwargs)
  File "chp2/track_deleter.py", line 32, in keypress
    self.selected.remove()
  File "/home/ben/miniconda/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-linux-x86_64.egg/matplotlib/artist.py", line 159, in remove
    self.axes = None
  File "/home/ben/miniconda/lib/python2.7/site-packages/matplotlib-1.5.dev1-py2.7-linux-x86_64.egg/matplotlib/lines.py", line 572, in axes
    if ax.xaxis is not None:
AttributeError: 'NoneType' object has no attribute 'xaxis'

Essentially, calling Line2D.axes = None as part of the remove process is triggering its property setter, and that property setter is assuming that an Axes object is always passed in.

[tacaswell]

I am on this one.