prevent 2D axis from showing up after calling Axes3D.cla()

Author: grlee77

lib/matplotlib/axes/_base.py

@@ -963,7 +963,7 @@ def cla(self):
         self.patch.set_linewidth(0)
         self.patch.set_transform(self.transAxes)
 
-        self.axison = True
+        self.set_axis_on()
 
         self.xaxis.set_clip_path(self.patch)
         self.yaxis.set_clip_path(self.patch)