new upload script with /mnt/sd card as backup

opencv-motion-detect/upload_video.py

@@ -124,7 +124,7 @@ def cleanup(target):
                 cnt += 1
         # clean up
         for f in oldest_n_files:
-            os.remove(f)
+            os.remove(str(f))
 
 def lookup(src, file, backup):
     file = src+ '/' + file