Minor corrections.

sql/mysqld.cc:
  Fixed: optimize_join_buffer_size was missing in the description of possible
  options for the optimizer switch.
sql/sql_select.cc:
  Fixed: initialization for the field ref_table_rows of the KEYUSE structure was 
  missing (as a result of a lame merge).

sql/mysqld.cc

@@ -7413,7 +7413,8 @@ thread is in the relay logs.",
    "index_condition_pushdown, firstmatch, loosescan, materialization, "
    "semijoin, partial_match_rowid_merge, partial_match_table_scan, "
    "subquery_cache, outer_join_with_cache, semijoin_with_cache, "
-   "join_cache_incremental, join_cache_hashed, join_cache_bka"
+   "join_cache_incremental, join_cache_hashed, join_cache_bka, "
+   "optimize_join_buffer_size"
 #ifndef DBUG_OFF
    ", table_elimination"
 #endif 

sql/sql_select.cc

@@ -4031,6 +4031,7 @@ add_keyuse(DYNAMIC_ARRAY *keyuse_array, KEY_FIELD *key_field,
   }
   keyuse.used_tables= key_field->val->used_tables();
   keyuse.optimize= key_field->optimize & KEY_OPTIMIZE_REF_OR_NULL;
+  keyuse.ref_table_rows= 0;
   keyuse.null_rejecting= key_field->null_rejecting;
   keyuse.cond_guard= key_field->cond_guard;
   keyuse.sj_pred_no= key_field->sj_pred_no;