message: Update download_dependencies.sh to prevent crash from 403
  * Update download_dependencies.sh for eigen
  The eigen bitbucket seems to have changed causing the scrip to crash with a unrecognized archive error.
  Changing to grep -v mirror.bazel seems to fix this because otherwise we get a 403 forbidden error.
  * Update download_dependencies.sh
diff: @@ -22,7 +22,14 @@ cd "$SCRIPT_DIR/../../.."
  DOWNLOADS_DIR=tensorflow/contrib/lite/downloads
  BZL_FILE_PATH=tensorflow/workspace.bzl
  -EIGEN_URL="$(grep -o 'http.*bitbucket.org/eigen/eigen/get/.*tar\.gz' "${BZL_FILE_PATH}" | grep -v bazel-mirror | head -n1)"
  +# Ensure it is being run from repo root
  +if [ ! -f $BZL_FILE_PATH ]; then
  + echo "Could not find ${BZL_FILE_PATH}":
  + echo "Likely you are not running this from the root directory of the repository.";
  + exit 1;
  +fi
  +
  +EIGEN_URL="$(grep -o 'http.*bitbucket.org/eigen/eigen/get/.*tar\.gz' "${BZL_FILE_PATH}" | grep -v mirror.bazel | head -n1)"
  GEMMLOWP_URL="$(grep -o 'https://mirror.bazel.build/github.com/google/gemmlowp/.*zip' "${BZL_FILE_PATH}" | head -n1)"
  GOOGLETEST_URL="https://github.com/google/googletest/archive/release-1.8.0.tar.gz"
  ABSL_URL="$(grep -o 'https://github.com/abseil/abseil-cpp/.*tar.gz' "${BZL_FILE_PATH}" | head -n1)"
  