Fix a typo in get_best_ror_intersect

cpk_scan should not be used if using it increases the cost of the query plan.

Author: spetrunia

sql/opt_range.cc

@@ -6529,6 +6529,8 @@ TRP_ROR_INTERSECT *get_best_ror_intersect(const PARAM *param, SEL_TREE *tree,
  if (ror_intersect_add(intersect, cpk_scan, TRUE) && 
  (intersect->total_cost < min_cost))
  intersect_best= intersect; //just set pointer here
+ else
+ cpk_scan= 0; // Don't use cpk_scan
  }
  else
  cpk_scan= 0; // Don't use cpk_scan