Update environment variable used to determine cuda_version (#785)

This PR updates the environment variable thats used to determine the `cuda_version` varaible in our conda recipes.

The `CUDA` environment variable is explicitly set by the Ops team in our Jenkins jobs, whereas `CUDA_VERSION` comes from the `nvidia/cuda` Docker images that we base our images from.

Authors:
  - AJ Schmidt (https://github.com/ajschmidt8)

Approvers:
  - Ray Douglass (https://github.com/raydouglass)

URL: #785

conda/recipes/librmm/meta.yaml

@@ -1,7 +1,7 @@
 # Copyright (c) 2018, NVIDIA CORPORATION.
 
 {% set version = environ.get('GIT_DESCRIBE_TAG', '0.0.0.dev').lstrip('v') + environ.get('VERSION_SUFFIX', '') %}
-{% set cuda_version='.'.join(environ.get('CUDA_VERSION', '9.2').split('.')[:2]) %}
+{% set cuda_version='.'.join(environ.get('CUDA', '9.2').split('.')[:2]) %}
 package:
   name: librmm
   version: {{ version }}

conda/recipes/rmm/meta.yaml

@@ -2,7 +2,7 @@
 
 {% set version = environ.get('GIT_DESCRIBE_TAG', '0.0.0.dev').lstrip('v') + environ.get('VERSION_SUFFIX', '') %}
 {% set py_version=environ.get('CONDA_PY', 35) %}
-{% set cuda_version='.'.join(environ.get('CUDA_VERSION', '10.1').split('.')[:2]) %}
+{% set cuda_version='.'.join(environ.get('CUDA', '10.1').split('.')[:2]) %}
 
 package:
   name: rmm