Fix import name

bob/pad/face/utils/__init__.py

 from .load_utils import (
     frames, number_of_frames, yield_faces, scale_face, blocks,
-    bbx_cropper, min_face_size_normalizer, color_augmentation, block_generator,
-    the_giant_video_loader)
+    bbx_cropper, min_face_size_normalizer, color_augmentation,
+    blocks_generator, the_giant_video_loader)
 
 # gets sphinx autodoc done right - don't remove it
 __all__ = [_ for _ in dir() if not _.startswith('_')]