message: Remove note about Ubuntu 14 incompatibility due to future change plans
diff: ## Breaking Changes
  * Prebuilt binaries are now built against CUDA 9 and cuDNN 7.
  -* Our Linux binaries are built using ubuntu 16 containers, potentially
  - introducing glibc incompatibility issues with ubuntu 14.
  * Starting from 1.6 release, our prebuilt binaries will use AVX instructions.
  This may break TF on older CPUs.
  