Fix bug in SparseLU dfs for dense matrices
Fix bug in SparseLU dfs for dense matrices

madlib/eigen_backup,madlib/eigen_backup,mjbshaw/Eigen,mjbshaw/Eigen,madlib/eigen_backup,rotorliu/eigen,rotorliu/eigen,mjbshaw/Eigen,rotorliu/eigen,rotorliu/eigen,mjbshaw/Eigen,madlib/eigen_backup