I see this in Python 3.6 test suites. Is this safe to ignore or should be fixed somehow? Should we move this to astropy-helpers? I am not sure where this is coming from.

home/travis/miniconda/envs/test/lib/python3.6/importlib/_bootstrap.py:205:
ImportWarning: can't resolve package from __spec__ or __package__,
falling back on __name__ and __path__

  return f(*args, **kwds)

p.s. Instead of decreasing the number of issues, I am increasing it. Sorry, @bsipocz !