fix the usage of np.min (#677)
fix the usage of np.min (#677)

Summary:
The first param of `np.min()` should be a list, `np.ndarray`, and so on, but not a float object.

Pull Request resolved: https://github.com/mapillary/OpenSfM/pull/677

Reviewed By: paulinus

Differential Revision: D25184730

Pulled By: YanNoun

fbshipit-source-id: 51a367dc7343dd45d8924edcae79eeb8d7618ba3

oscarlorentzon/OpenSfM,oscarlorentzon/OpenSfM,oscarlorentzon/OpenSfM,mapillary/OpenSfM,mapillary/OpenSfM,oscarlorentzon/OpenSfM,mapillary/OpenSfM,mapillary/OpenSfM,mapillary/OpenSfM,oscarlorentzon/OpenSfM