Remove unused variables

Change-Id: Ieaecce32d8a94c61876e097b957627d689e72fe7

internal/ceres/parallel_vector_operations_benchmark.cc

diff --git a/internal/ceres/parallel_vector_operations_benchmark.cc b/internal/ceres/parallel_vector_operations_benchmark.cc
index 31a5c7a..7e523c3 100644
--- a/internal/ceres/parallel_vector_operations_benchmark.cc
+++ b/internal/ceres/parallel_vector_operations_benchmark.cc
@@ -253,7 +253,6 @@
   const double a = 3.1415;
   const double b = 1.2345;
 
-  double total = 0.;
   for (auto _ : state) {
     z = a * x + b * y;
   }
@@ -272,7 +271,6 @@
   const double a = 3.1415;
   const double b = 1.2345;
 
-  double total = 0.;
   for (auto _ : state) {
     Axpby(a, x, b, y, z, &context, num_threads);
   }