Drop redundant dependency from download_models.py

samples/dnn/download_models.py

@@ -3,7 +3,6 @@ Helper module to download extra data from Internet
 '''
 from __future__ import print_function
 import os
-import cv2
 import sys
 import yaml
 import argparse
@@ -361,4 +360,4 @@ if __name__ == '__main__':
         if selected_model_name and not m.name.startswith(selected_model_name):
             continue
         print('Model: ' + selected_model_name)
-        m.get()
+        m.get()