Follow-up for the fix for bug #18153 "ALTER/OPTIMIZE/REPAIR on transactional

tables corrupt triggers".

It turned out that we also have relied at certain places that
(new_table != table_name) were always true on Windows and for transactional
tables. Since our fix for the bug brakes this assumption we have to add new
flag to pass this information around.
This code needs to be refactored but I dare not to do this in 5.0.

sql/sql_table.cc

@@ -3182,6 +3182,7 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
   uint db_create_options, used_fields;
   enum db_type old_db_type,new_db_type;
   bool need_copy_table;
+  bool no_table_reopen= FALSE;
   DBUG_ENTER("mysql_alter_table");
 
   thd->proc_info="init";
@@ -3833,6 +3834,7 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
     */
     close_cached_table(thd, table);
     table=0;					// Marker that table is closed
+    no_table_reopen= TRUE;
   }
 #if (!defined( __WIN__) && !defined( __EMX__) && !defined( OS2))
   else
@@ -3871,7 +3873,7 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
     VOID(pthread_mutex_unlock(&LOCK_open));
     goto err;
   }
-  if (thd->lock || new_name != table_name)	// True if WIN32
+  if (thd->lock || new_name != table_name || no_table_reopen)  // True if WIN32
   {
     /*
       Not table locking or alter table with rename