fix minor typos

all timing values in the summary are initialized to -1, so the one
+1 is likely an oversight.

Change-Id: Ie355f3b7da08a56d49d19ca9a5bc48fe5581dee3

include/ceres/solver.h

@@ -839,7 +839,7 @@ class CERES_EXPORT Solver {
     int num_linear_solves = -1;
 
     // Time (in seconds) spent evaluating the residual vector.
-    double residual_evaluation_time_in_seconds = 1.0;
+    double residual_evaluation_time_in_seconds = -1.0;
 
     // Number of residual only evaluations.
     int num_residual_evaluations = -1;

internal/ceres/levenberg_marquardt_strategy.h

@@ -78,7 +78,7 @@ class LevenbergMarquardtStrategy : public TrustRegionStrategy {
   // Scaled copy of diagonal_. Stored here as optimization to prevent
   // allocations in every iteration and reuse when a step fails and
   // ComputeStep is called again.
-  Vector lm_diagonal_;  // lm_diagonal_ = diagonal_ / radius_;
+  Vector lm_diagonal_;  // lm_diagonal_ = sqrt(diagonal_ / radius_);
 };
 
 }  // namespace internal