Remove dependences of cv2#27286

Merged

LielinJiang merged 7 commits intoPaddlePaddle:developfrom

LielinJiang:rm-cv2

Sep 18, 2020

Commits on Sep 14, 2020

Commits on Sep 15, 2020

rm opencv dependence
LielinJiang
committed

Commits on Sep 16, 2020

Commits on Sep 17, 2020

fix docs, test=document_fix
LielinJiang
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