Add the 2_d_d SchurEliminator specialization.

This occurs far too often in bundle adjustment problems to be ignored.

Change-Id: Ib137f1566acf5fffa63e50a55fe8e78ea9eb1c14
diff --git a/internal/ceres/schur_eliminator.cc b/internal/ceres/schur_eliminator.cc
index 31f8354..25103dc 100644
--- a/internal/ceres/schur_eliminator.cc
+++ b/internal/ceres/schur_eliminator.cc
@@ -37,7 +37,7 @@
 // THIS FILE IS AUTOGENERATED. DO NOT EDIT.
 //=========================================
 //
-// This file is generated using generate_eliminator_specializations.py.
+// This file is generated using generate_eliminator_specialization.py.
 // Editing it manually is not recommended.
 
 #include "ceres/linear_solver.h"
@@ -105,6 +105,11 @@
       (options.f_block_size == Eigen::Dynamic)) {
     return new SchurEliminator<2, 4, Eigen::Dynamic>(options);
   }
+  if ((options.row_block_size == 2) &&
+      (options.e_block_size == Eigen::Dynamic) &&
+      (options.f_block_size == Eigen::Dynamic)) {
+    return new SchurEliminator<2, Eigen::Dynamic, Eigen::Dynamic>(options);
+  }
   if ((options.row_block_size == 4) &&
       (options.e_block_size == 4) &&
       (options.f_block_size == 2)) {