Ergonomic, hermetic, user-friendly software build system for Python, Go, Java, Kotlin, Protobuf, Scala, Shell. Pants lets you fearlessly scale up your codebase!

Pants

I got some errors in my PR that look like it had trouble downloading some go file:

```
                     E   	  File "/home/travis/build/pantsbuild/pants/contrib/go/src/python/pants/contrib/go/subsystems/fetchers.py", line 401, in _fetch
                     E   	    with self._download(url) as download_path:
                     E   	  File "/opt/python/2.7.9/lib/python2.7/contextlib.py", line 17, in __enter__
                     E   	    return self.gen.next()
                     E   	  File "/home/travis/build/pantsbuild/pants/contrib/go/src/python/pants/contrib/go/subsystems/fetchers.py", line 418, in _download
                     E   	    raise self.FetchError('Failed to download {} ({} error)'.format(url, res.status_code))
                     E   	
                     E   	Exception message: Failed to download <https://github.com/kr/pretty/archive/bc9499caa0f45ee5edb2f0209fbd61fbf3d9018f.tar.gz> (502 error)
```
would anyone mind restarting this?