Fix CircleCI test failures (#2069)

Summary:
The unit test failures seems to be caused by [conda 4.11](https://github.com/conda/conda/issues/11096)
Remove conda update line fixes the issue.

Pull Request resolved: https://github.com/pytorch/audio/pull/2069

Reviewed By: carolineechen

Differential Revision: D33023851

Pulled By: nateanl

fbshipit-source-id: 73246189d4ccc541e366a5367f532a5b456af8f8

.circleci/unittest/linux/scripts/setup_env.sh

@@ -24,7 +24,6 @@ if [ ! -d "${conda_dir}" ]; then
     wget --quiet -O miniconda.sh "http://repo.continuum.io/miniconda/Miniconda3-latest-${os}-x86_64.sh"
     bash ./miniconda.sh -b -f -p "${conda_dir}"
     eval "$("${conda_dir}/bin/conda" shell.bash hook)"
-    conda update --quiet -y conda
     printf "* Updating the base Python version to %s\n" "${PYTHON_VERSION}"
     conda install --quiet -y python="${PYTHON_VERSION}"
 else

.circleci/unittest/windows/scripts/setup_env.sh

@@ -24,7 +24,6 @@ if [ ! -d "${conda_dir}" ]; then
     unset tmp_conda
     unset miniconda_exe
     eval "$("${conda_dir}/Scripts/conda.exe" 'shell.bash' 'hook')"
-    conda update --quiet -y conda
     printf "* Updating the base Python version to %s\n" "${PYTHON_VERSION}"
     conda install --quiet -y python="$PYTHON_VERSION"
 else