Remove unused attribute in tests.

anntzer · anntzer · commit e40a9efb2dba · 2018-07-26T01:45:04.000+02:00
Should have been removed as part of 0c11fd7; there is no other mention of this attribute in the codebase.
diff --git a/lib/matplotlib/tests/test_animation.py b/lib/matplotlib/tests/test_animation.py
@@ -22,8 +22,6 @@ class NullMovieWriter(animation.AbstractMovieWriter):
     it cannot be added to the 'writers' registry.
     """
 
-    frame_size_can_vary = True
-
     def setup(self, fig, outfile, dpi, *args):
         self.fig = fig
         self.outfile = outfile
