Fix for bug in set_cmap in NonUniformImage

[Cadair]

I think this is a legitimate bug and attached fix.

Running the regression test without the fix produced the following error:

Traceback (most recent call last):
  File "/opt/miniconda/envs/matplotlib-dev/lib/python2.7/site-packages/nose/case.py", line 197, in runTest
    self.test(*self.arg)
  File "test_image.py", line 447, in test_nonuniformimage_setcmap
    im.set_cmap('Blues')
  File "/home/stuart/GitHub/matplotlib/lib/matplotlib/image.py", line 855, in set_cmap
    super(NonUniformImage, self).set_cmap(self, cmap)
TypeError: set_cmap() takes exactly 2 arguments (3 given)

[Tillsten]

Looks right.

[WeatherGod]

needs a @cleanup in order to prevent inadvertent side-effects for other tests.

[WeatherGod]

By the way, could you also fix the same bug for set_norm just above?

[Cadair]

@WeatherGod updated.

[WeatherGod]

Good catch! Thanks!

[Cadair]

No problem. :)

[tacaswell]

Gah, sorry I put those lines in 😱 .

Thanks for cleaning up my mess 😄