Avoiding the Warning: "deprecated conversion from string constant to char*"

Change-Id: Ifa47f9b0724f79c5c695828628c89818ddefd844
diff --git a/internal/ceres/schur_complement_solver.cc b/internal/ceres/schur_complement_solver.cc
index bc9e28a..e1be4e2 100644
--- a/internal/ceres/schur_complement_solver.cc
+++ b/internal/ceres/schur_complement_solver.cc
@@ -293,7 +293,7 @@
     }
 
     if (VLOG_IS_ON(2)) {
-      cholmod_print_common("Symbolic Analysis", ss_.mutable_cc());
+      cholmod_print_common(const_cast<char*>("Symbolic Analysis"), ss_.mutable_cc());
     }
   }
 
diff --git a/internal/ceres/sparse_normal_cholesky_solver.cc b/internal/ceres/sparse_normal_cholesky_solver.cc
index 7946665..195cacb 100644
--- a/internal/ceres/sparse_normal_cholesky_solver.cc
+++ b/internal/ceres/sparse_normal_cholesky_solver.cc
@@ -215,7 +215,7 @@
     }
 
     if (VLOG_IS_ON(2)) {
-      cholmod_print_common("Symbolic Analysis", ss_.mutable_cc());
+      cholmod_print_common(const_cast<char*>("Symbolic Analysis"), ss_.mutable_cc());
     }
   }
 
diff --git a/internal/ceres/visibility_based_preconditioner.cc b/internal/ceres/visibility_based_preconditioner.cc
index 9c92190..1678d00 100644
--- a/internal/ceres/visibility_based_preconditioner.cc
+++ b/internal/ceres/visibility_based_preconditioner.cc
@@ -428,7 +428,7 @@
     }
 
     if (VLOG_IS_ON(2)) {
-      cholmod_print_common("Symbolic Analysis", ss_.mutable_cc());
+      cholmod_print_common(const_cast<char*>("Symbolic Analysis"), ss_.mutable_cc());
     }
   }