Fix backend_driver.py fails on non-existent files

Author: cgohlke

examples/tests/backend_driver.py

@@ -70,7 +70,8 @@
     ]
 
 files['images'] = [
-    'imshow_demo.py',
+    'image_demo.py',
+    'contourf_log.py',
     ]
 
 files['statistics'] = [
@@ -135,7 +136,6 @@
     'contour_image.py',
     'contour_label_demo.py',
     'contourf_demo.py',
-    'contourf_log.py',
     'coords_demo.py',
     'coords_report.py',
     'csd_demo.py',