The automatic DROP TEMPORARY TABLE is now DROP TEMPORARY TABLE IF EXISTS,

this is better in this case:
- imagine user1 has created a temp table
- imagine user2 does FLUSH TABLES WITH READ LOCK, then takes a backup,
then RESET MASTER then UNLOCK TABLES, like mysqldump --first-slave
- then in the binlog you will finally have the DROP TEMPORARY TABLE,
but not the CREATE TEMPORARY TABLE, so when you later restore with
mysqlbinlog|mysql, mysql will complain that table does not exist.
Replication was already protected of this (it processes DROP TEMPORARY
TABLE as if there was a IF EXISTS), now I add it directly to the query
for mysqlbinlog|mysql to work.


mysql-test/r/drop_temp_table.result:
  result update (query changed)

mysql-test/r/drop_temp_table.result

@@ -13,6 +13,6 @@ Log_name	Pos	Event_type	Server_id	Orig_log_pos	Info
 master-bin.001	4	Start	1	4	Server ver: VERSION, Binlog ver: 3
 master-bin.001	79	Query	1	79	use `test`; create database `drop-temp+table-test`
 master-bin.001	152	Query	1	152	use `drop-temp+table-test`; create temporary table `table:name` (a int)
-master-bin.001	246	Query	1	246	use `drop-temp+table-test`; DROP /*!40005 TEMPORARY */ TABLE `drop-temp+table-test`.`table:name`
-master-bin.001	365	Query	1	365	use `drop-temp+table-test`; DO RELEASE_LOCK("a")
+master-bin.001	246	Query	1	246	use `drop-temp+table-test`; DROP /*!40005 TEMPORARY */ TABLE IF EXISTS `drop-temp+table-test`.`table:name`
+master-bin.001	375	Query	1	375	use `drop-temp+table-test`; DO RELEASE_LOCK("a")
 drop database `drop-temp+table-test`;

sql/sql_base.cc

@@ -547,7 +547,7 @@ void close_temporary_tables(THD *thd)
     return;
   
   LINT_INIT(end);
-  query_buf_size= 50;   // Enough for DROP ... TABLE
+  query_buf_size= 50;   // Enough for DROP ... TABLE IF EXISTS
 
   for (table=thd->temporary_tables ; table ; table=table->next)
     /*
@@ -558,7 +558,8 @@ void close_temporary_tables(THD *thd)
     query_buf_size+= table->key_length+1;
 
   if ((query = alloc_root(&thd->mem_root, query_buf_size)))
-    end=strmov(query, "DROP /*!40005 TEMPORARY */ TABLE ");
+    // Better add "if exists", in case a RESET MASTER has been done
+    end=strmov(query, "DROP /*!40005 TEMPORARY */ TABLE IF EXISTS ");
 
   for (table=thd->temporary_tables ; table ; table=next)
   {