Fix lint errors

Change-Id: I368075a235b4404bb80cd5a7a91f0dad2d202137

internal/ceres/block_jacobi_preconditioner.cc

diff --git a/internal/ceres/block_jacobi_preconditioner.cc b/internal/ceres/block_jacobi_preconditioner.cc
index db70abf..a12e34e 100644
--- a/internal/ceres/block_jacobi_preconditioner.cc
+++ b/internal/ceres/block_jacobi_preconditioner.cc
@@ -109,7 +109,7 @@
   int* m_cols = m_->mutable_cols();
   int* m_rows = m_->mutable_rows();
   m_rows[0] = 0;
-  for (int i = 0, col = 0, idx = 0; i < num_col_blocks; ++i) {
+  for (int i = 0, idx = 0; i < num_col_blocks; ++i) {
     // For each column block populate a diagonal block in the preconditioner.
     // Not that the because of the way the CompressedRowSparseMatrix format
     // works, the entire diagonal block is laid out contiguously in memory as a
@@ -143,7 +143,6 @@
   double* m_values = m_->mutable_values();
   const int* m_rows = m_->rows();
 
-  const int num_rows = A.num_rows();
   for (int i = 0; i < num_row_blocks; ++i) {
     const int row = row_blocks[i].position;
     const int row_block_size = row_blocks[i].size;

internal/ceres/compressed_col_sparse_matrix_utils.cc

diff --git a/internal/ceres/compressed_col_sparse_matrix_utils.cc b/internal/ceres/compressed_col_sparse_matrix_utils.cc
index 8d94ec2..995d8da 100644
--- a/internal/ceres/compressed_col_sparse_matrix_utils.cc
+++ b/internal/ceres/compressed_col_sparse_matrix_utils.cc
@@ -49,7 +49,6 @@
   CHECK(block_cols != nullptr);
   block_rows->clear();
   block_cols->clear();
-  const int num_row_blocks = row_blocks.size();
   const int num_col_blocks = col_blocks.size();
 
   // This loop extracts the block sparsity of the scalar sparse matrix