Fix multiple errors involving bindings, and fix result codes.

- Cause an error to be raised by an unresolved binding in a configuration file.
- Fix incorrect structuring of processed bindings.
- Add a test to confirm that unbound parameters generate errors.

While I'm in the code, also fix a problem where result codes aren't returned correctly
to the shell.

Bugs closed: aurora-781

Reviewed at https://reviews.apache.org/r/26270/