message: Update docstrings in `configure.py`
  HDFS is now supported through bazel build config and not through a flag in this file (`configure.py`).
  However, the docstrings still refer to it. Replaced it with `TF_NEED_CUDA`, which is still a flag set in this script
diff: @@ -293,9 +293,9 @@ def get_var(environ_cp,
  Args:
  environ_cp: copy of the os.environ.
  - var_name: string for name of environment variable, e.g. "TF_NEED_HDFS".
  - query_item: string for feature related to the variable, e.g. "Hadoop File
  - System".
  + var_name: string for name of environment variable, e.g. "TF_NEED_CUDA".
  + query_item: string for feature related to the variable, e.g. "CUDA for
  + Nvidia GPUs".
  enabled_by_default: boolean for default behavior.
  question: optional string for how to ask for user input.
  yes_reply: optional string for reply when feature is enabled.
  @@ -376,9 +376,9 @@ def set_build_var(environ_cp,
  Args:
  environ_cp: copy of the os.environ.
  - var_name: string for name of environment variable, e.g. "TF_NEED_HDFS".
  - query_item: string for feature related to the variable, e.g. "Hadoop File
  - System".
  + var_name: string for name of environment variable, e.g. "TF_NEED_CUDA".
  + query_item: string for feature related to the variable, e.g. "CUDA for
  + Nvidia GPUs".
  option_name: string for option to define in .bazelrc.
  enabled_by_default: boolean for default behavior.
  bazel_config_name: Name for Bazel --config argument to enable build feature.
  @@ -411,9 +411,9 @@ def set_action_env_var(environ_cp,
  Args:
  environ_cp: copy of the os.environ.
  - var_name: string for name of environment variable, e.g. "TF_NEED_HDFS".
  - query_item: string for feature related to the variable, e.g. "Hadoop File
  - System".
  + var_name: string for name of environment variable, e.g. "TF_NEED_CUDA".
  + query_item: string for feature related to the variable, e.g. "CUDA for
  + Nvidia GPUs".
  enabled_by_default: boolean for default behavior.
  question: optional string for how to ask for user input.
  yes_reply: optional string for reply when feature is enabled.
  @@ -570,7 +570,7 @@ def get_from_env_or_user_or_default(environ_cp, var_name, ask_for_var,
  Args:
  environ_cp: copy of the os.environ.
  - var_name: string for name of environment variable, e.g. "TF_NEED_HDFS".
  + var_name: string for name of environment variable, e.g. "TF_NEED_CUDA".
  ask_for_var: string for how to ask for user input.
  var_default: default value string.
  