opencv-python-headless should be enough, and easier to deploy

[ocourtin]

Hi,

It looks like nothing, but could really make packager life easier.
As opencv-python imply several extra libs to be installed on system (such as libSM).

Thanks in advance,

[albu]

hi, thanks for the pr.
would it install opencv-python-headless in case if opencv-python is already installed?

[ocourtin]

@albu

would it install opencv-python-headless in case if opencv-python is already installed?

Yes indeed.

But the point is that you cannot only trust pip on this one,
as opencv-python can be installed but not able to works as some lib dependencies missed...