Remove ParameterBlock::state_offset as it is not used.

Change-Id: I3d6fbe333dde73ceb4c6c5e01460aa997883889f
diff --git a/internal/ceres/solver_impl.cc b/internal/ceres/solver_impl.cc
index e16b6a0..c45c194 100644
--- a/internal/ceres/solver_impl.cc
+++ b/internal/ceres/solver_impl.cc
@@ -733,7 +733,7 @@
     linear_solver_options.elimination_groups.push_back(it->second.size());
   }
   // Schur type solvers, expect at least two elimination groups. If
-  // there is only one elimination group, then CreateReducedProblem
+  // there is only one elimination group, then CreateReducedProgram
   // guarantees that this group only contains e_blocks. Thus we add a
   // dummy elimination group with zero blocks in it.
   if (IsSchurType(linear_solver_options.type) &&