fix clear env

.evergreen/download-mongodb.sh

@@ -717,7 +717,7 @@ download_and_extract_package ()
  chmod -R +x mongodb
  # Clear the environment to avoid "find: The environment is too large for exec()"
  # error on Windows.
- env -i PATH=$PATH find . -name vcredist_x64.exe -exec {} /install /quiet \;
+ env -i PATH="$PATH" find . -name vcredist_x64.exe -exec {} /install /quiet \;
  echo "MongoDB server version: $(./mongodb/bin/mongod --version)"
  cd -
 }