Remove unused code from the Khmer shaper.
diff --git a/src/hb-ot-shape-complex-khmer.cc b/src/hb-ot-shape-complex-khmer.cc
index fd8a9be..3da8374 100644
--- a/src/hb-ot-shape-complex-khmer.cc
+++ b/src/hb-ot-shape-complex-khmer.cc
@@ -161,8 +161,6 @@
 
   mutable hb_codepoint_t virama_glyph;
 
-  hb_indic_would_substitute_feature_t pref;
-
   hb_mask_t mask_array[KHMER_NUM_FEATURES];
 };
 
@@ -175,8 +173,6 @@
 
   khmer_plan->virama_glyph = (hb_codepoint_t) -1;
 
-  khmer_plan->pref.init (&plan->map, HB_TAG('p','r','e','f'), true);
-
   for (unsigned int i = 0; i < ARRAY_LENGTH (khmer_plan->mask_array); i++)
     khmer_plan->mask_array[i] = (khmer_features[i].flags & F_GLOBAL) ?
 				 0 : plan->map.get_1_mask (khmer_features[i].tag);