text: Title: receiving error with face_encoding of face_recognition library after cuda setup
  Body: * face_recognition version: 1.2.3
  * Python version: 3.6.5
  * Operating System: windows 10
  
  
  ### What I Did
  I have just setup my CUDA with dlib and after that I am receiving this error when running the encoding of face using face_recognition library
  ```
  face_encodings = face_recognition.face_encodings(frame, face_locations, num_jitters=1)
  
    File "C:\Users\abhinav.jhanwar\AppData\Local\Continuum\anaconda3\lib\site-packages\face_recognition\api.py", line 210, in face_encodings
      :return: A list of 128-dimensional face encodings (one for each face in the image)
  
    File "C:\Users\abhinav.jhanwar\AppData\Local\Continuum\anaconda3\lib\site-packages\face_recognition\api.py", line 210, in <listcomp>
      :return: A list of 128-dimensional face encodings (one for each face in the image)
  
  RuntimeError: Error while calling cudnnCreate(&handles[new_device_id]) in file C:\dlib-master\dlib-master\dlib\cuda\cudnn_dlibapi.cpp:104. code: 1, reason: CUDA Runtime API initialization failed.
  ```
  