fix: use rotation in case of missing GPS/GCPs
fix: use rotation in case of missing GPS/GCPs

Summary: This Diff loosen the alignment procedure with orientation priors, by relaxing the need of GPS/GCPs : in that case, we can still use the rotation for alignment (identity scale and translation).

Reviewed By: fabianschenk

Differential Revision: D36478909

fbshipit-source-id: 3a679a75cb15b0da0bbeda3b20f2993f658ff6fb

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