Fix some error reporting issues.

1. Let the new options system throw exceptions to the top in the
   usual way.  We already have error handling there.

2. Ensure that if we throw an exception to the top we report our
   status as FAILURE, not SUCCESS.

Reviewed at https://rbcommons.com/s/twitter/r/1113/
Merge remote-tracking branch 'pantsbuild/master'
Sync of https://github.com/pantsbuild/pants/commit/dbe0d8f5f1f1efbcdb68190c0d2789fcbd657646