FYI the OSX 10.12 Sierra shard is flaky when running

PANTS_ENABLE_PANTSD=true ./pants', 'list', '::'

with 1.15.0.dev3. Gets a segfault / NailgunError https://travis-ci.org/pantsbuild/setup/jobs/506364098#L317 I’ve only seen this on the 10.12 shard, not 10.11 or 10.13