Remove unused-variable in mapillary/opensfm/opensfm/src/bundle/error/…

…absolute_motion_errors.h

Summary:
LLVM-15 has a warning `-Wunused-variable` which we treat as an error because it's so often diagnostic of a code issue. Unused variables can compromise readability or, worse, performance.

This diff either (a) removes an unused variable and, possibly, it's associated code or (b) qualifies the variable with `[[maybe_unused]]`.

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Reviewed By: meyering

Differential Revision: D64279137

fbshipit-source-id: 68f17d9881c727d38065cd80d8314d28ac325f52

opensfm/src/bundle/error/absolute_motion_errors.h

@@ -93,7 +93,6 @@ struct RollAngleError {
     T ex[3] = {T(1), T(0), T(0)};  // A point to the right of the camera (x=1)
     T ez[3] = {T(0), T(0), T(1)};  // A point in front of the camera (z=1)
     T Rt_ex[3], Rt_ez[3];
-    T tangle_ = T(angle_);
     ceres::AngleAxisRotatePoint(R.data(), ex, Rt_ex);
     ceres::AngleAxisRotatePoint(R.data(), ez, Rt_ez);