don't auto-set nvcc host compiler with cmake >2.8.9

don't auto-set nvcc host compiler with cmake >2.8.9

Starting with CMake 2.8.10 the FindCUDA module set sets the nvcc host
compiler by default which clashes with our internal implementation of
the same feature. To support both pre-2.8.10 and later versions, this
change renames the CUDA_NVCC_HOST_COMPILER cache variable to
CUDA_HOST_COMPILER (used by CMake 2.8.10's FindCUDA) and avoids adding
the -ccbin option to the nvcc flags with CMake 2.8.10 and later.

Fixes #1051

Change-Id: I4d4048d520edb8655b88b6bae35f97df76a25910