fixed bug with thd->allow_sum_func value in subselect

mysql-test/r/subselect.result:
  test of sum function with subselect
mysql-test/t/subselect.test:
  test of sum function with subselect

mysql-test/r/subselect.result

@@ -12,6 +12,9 @@ SELECT (SELECT 1 FROM (SELECT 1) HAVING a=1) as a;
 Reference 'a' not supported (forward reference in item list)
 SELECT (SELECT 1 FROM (SELECT 1) HAVING b=1) as a,(SELECT 1 FROM (SELECT 1) HAVING a=1) as b;
 Reference 'b' not supported (forward reference in item list)
+SELECT (SELECT 1),MAX(1) FROM (SELECT 1);
+(SELECT 1)	MAX(1)
+1	1
 drop table if exists t1,t2,t3,t4,t5,attend,clinic,inscrit;
 create table t1 (a int);
 create table t2 (a int, b int);

mysql-test/t/subselect.test

@@ -5,6 +5,7 @@ SELECT (SELECT (SELECT 0 UNION SELECT 0));
 SELECT (SELECT 1 FROM (SELECT 1) HAVING a=1) as a;
 -- error 1245
 SELECT (SELECT 1 FROM (SELECT 1) HAVING b=1) as a,(SELECT 1 FROM (SELECT 1) HAVING a=1) as b;
+SELECT (SELECT 1),MAX(1) FROM (SELECT 1);
 drop table if exists t1,t2,t3,t4,t5,attend,clinic,inscrit;
 create table t1 (a int);
 create table t2 (a int, b int);

sql/sql_base.cc

@@ -2225,8 +2225,10 @@ int setup_conds(THD *thd,TABLE_LIST *tables,COND **conds)
 {
   DBUG_ENTER("setup_conds");
   thd->set_query_id=1;
-  thd->cond_count=0;
-  thd->allow_sum_func=0;
+  
+  thd->cond_count= 0;
+  bool save_allow_sum_func= thd->allow_sum_func;
+  thd->allow_sum_func= 0;
   if (*conds)
   {
     thd->where="where clause";
@@ -2299,6 +2301,7 @@ int setup_conds(THD *thd,TABLE_LIST *tables,COND **conds)
 	table->on_expr=and_conds(table->on_expr,cond_and);
     }
   }
+  thd->allow_sum_func= save_allow_sum_func;
   DBUG_RETURN(test(thd->fatal_error));
 }