Fix camera conversions to colmap
Fix camera conversions to colmap

Summary: Corrected the export of brown and fisheye_opencv cameras to COLMAP

Reviewed By: arknapit

Differential Revision: D29389915

fbshipit-source-id: 1fc5f2ae9cf04ac5c625095697b132cc6523025b

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