LinearSolver::Options::num_eliminate_blocks is dead.

Replaced with LinearSolver::Options::elimination_groups.

Change-Id: I7c07542ec19279a35ddf6da498d417a79395c77f
diff --git a/internal/ceres/schur_complement_solver.h b/internal/ceres/schur_complement_solver.h
index ea1b318..c382f95 100644
--- a/internal/ceres/schur_complement_solver.h
+++ b/internal/ceres/schur_complement_solver.h
@@ -97,13 +97,14 @@
 // The two solvers can be instantiated by calling
 // LinearSolver::CreateLinearSolver with LinearSolver::Options::type
 // set to DENSE_SCHUR and SPARSE_SCHUR
-// respectively. LinearSolver::Options::num_eliminate_blocks should be
+// respectively. LinearSolver::Options::elimination_groups[0] should be
 // at least 1.
 class SchurComplementSolver : public BlockSparseMatrixBaseSolver {
  public:
   explicit SchurComplementSolver(const LinearSolver::Options& options)
       : options_(options) {
-    CHECK_GT(options.num_eliminate_blocks, 0);
+    CHECK_GT(options.elimination_groups.size(), 1);
+    CHECK_GT(options.elimination_groups[0], 0);
   }
 
   // LinearSolver methods