LinearSolver::Summary::status -> LinearSolver::Summary::message.

And a bunch of minor lint cleanups as they showed up.

Change-Id: I430a6b05710923c72daf6a5df4dfcd16fbf44b3a

internal/ceres/linear_solver.h

diff --git a/internal/ceres/linear_solver.h b/internal/ceres/linear_solver.h
index fb50d7e..fa151e0 100644
--- a/internal/ceres/linear_solver.h
+++ b/internal/ceres/linear_solver.h
@@ -273,7 +273,7 @@
     double residual_norm;
     int num_iterations;
     LinearSolverTerminationType termination_type;
-    string status;
+    string message;
   };
 
   virtual ~LinearSolver();