Fix set_limit to be uniform with all calls.

Fix of set_limit in case of an error (actually impossible case but better it will be right)

sql/sql_derived.cc

@@ -750,7 +750,7 @@ bool mysql_derived_optimize(THD *thd, LEX *lex, TABLE_LIST *derived)
     if (!derived->is_merged_derived())
     {
       JOIN *join= first_select->join;
-      unit->set_limit(first_select);
+      unit->set_limit(unit->global_parameters);
       unit->optimized= TRUE;
       if ((res= join->optimize()))
         goto err;
@@ -865,7 +865,7 @@ bool mysql_derived_fill(THD *thd, LEX *lex, TABLE_LIST *derived)
   }
   else
   {
-    unit->set_limit(first_select);
+    unit->set_limit(unit->global_parameters);
     if (unit->select_limit_cnt == HA_POS_ERROR)
       first_select->options&= ~OPTION_FOUND_ROWS;
 

sql/sql_lex.cc

@@ -2847,7 +2847,7 @@ void st_select_lex_unit::set_limit(st_select_lex *sl)
 
       DBUG_ASSERT(fix_fields_successful);
     }
-    val= fix_fields_successful ? item->val_uint() : HA_POS_ERROR;
+    val= fix_fields_successful ? item->val_uint() : 0;
   }
   else
     val= ULL(0);