math/ceres-solver: disable EIGENSPARSE by default like upstream
During configure stage the following
=============================================================== Enabling the use of Eigen as a sparse linear algebra library for solving the nonlinear least squares problems. Enabling this option results in an LGPL licensed version of Ceres Solver as the Simplicial Cholesky factorization in Eigen is licensed under the LGPL. ===============================================================
turns into
=============================================================== Disabling the use of Eigen as a sparse linear algebra library. This does not affect the covariance estimation algorithm which can still use the EIGEN_SPARSE_QR algorithm. ===============================================================