fix: fix dummy reconstruction creation
fix: fix dummy reconstruction creation

Summary:
This Diff fixes the output of the reconstructon representing the pre-calibrated rig instances.

Was broken few months ago, while making rigs 1st-class citizens.

Reviewed By: DodgySpaniard

Differential Revision: D33660486

fbshipit-source-id: b48b4cf6fddfb91d69c5a7e3e7754609fb7fb9a5

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