Fix a couple errors caught by the SciPy build process

[nbelakovski]

SciPy complained about "expression result unused" for the extra ')' in the repr function, which makes sense.

It also complained about rc being unused. This is slightly annoying because we put the return value of prima_minimize in result.status. I decided it made sense to return info by itself if there was an error in either init_result or check_problem, and then just return DFT by default.