message: Remove InterpolationManager::GetKey.
diff: @@ -619,21 +619,6 @@ public:
  }
  private:
  - /** @brief Get the key to indentify the corase to fine interpolation */
  - static Key GetKey(const Mesh::FaceInformation &face,
  - const DenseMatrix* ptMat)
  - {
  - // In the case of non-conforming slave shared face the master face is elem1.
  - const int nc_side =
  - (face.conformity == Mesh::FaceConformity::NonConformingSlave &&
  - face.location == Mesh::FaceLocation::Shared) ? 0 : 1;
  - const int face_key = nc_side == 1 ?
  - face.elem_1_local_face + 6*face.elem_2_local_face :
  - face.elem_2_local_face + 6*face.elem_1_local_face ;
  - // Unfortunately we can't trust unicity of the ptMat to identify the transformation.
  - return Key{ptMat, face_key};
  - }
  -
  /** @brief Returns the interpolation operator from a master (coarse) face to
  a slave (fine) face.
  