Next question, why did you have nvidia-opencl-icd in the first place? I suspect the answer is probably https://bugs.debian.org/739176 which has already been fixed.
It can't be pyopencl if it's still installed (that now Depends: libopencl-1.2-1 and both providers of that Conflict: libopencl1 as provided by nvidia-libopencl1), but it could have been if it were then removed (perhaps after noticing that it didn't work). The only other Depends or Recommends on opencl-icd in the current archive is bfgminer.
(If you actually want to use OpenCL on Intel hardware, you need beignet from experimental (the version in unstable/testing is too old to support Haswell) and ocl-icd-libopencl1, but the absence of those shouldn't break graphics.)