Implement WL#5502 Remove dead 5.0 class Sensitive_cursor.

Remove dead and unused code.
Update to reflect the code review requests.

include/thr_lock.h:
  Remove declarations for THR_LOCK_OWNER,
  added along with the patch for sensitive cursors.
mysys/thr_lock.c:
  Remove support for multiple thr_lock requestors
  per THD.
sql/lock.cc:
  Revert the patch that added support for sensitive cursors.
sql/sp_rcontext.cc:
  Updated the use of mysql_open_cursor().
sql/sql_class.cc:
  Move the instance of Server_side_cursor
  from class Prepared_statement to class Statement.
sql/sql_class.h:
  Move the isntance of Server_side_cursor
  from class Prepared_statement to class
  Statement.
  Remove multiple lock_ids of thr_lock.
sql/sql_cursor.cc:
  Remove Sensitive_cursor implementation.
sql/sql_cursor.h:
  Remove declarations for sensitive cursors.
sql/sql_prepare.cc:
  Move the declaration of instance of Server_side_cursor
  from class Statement to class Prepared_statement, 
  where it's used.
sql/sql_select.cc:
  Remove sensitive cursor support.
sql/sql_select.h:
  Remove sensitive cursor support.
sql/sql_union.cc:
  Remove sensitive cursor support.

1 files changed, 1 insertions, 2 deletions

diff --git a/sql/sql_union.cc b/sql/sql_union.cc
index 9ca4556524f..acc0f704c44 100644
--- a/sql/sql_union.cc
+++ b/sql/sql_union.cc
@@ -36,8 +36,7 @@ bool mysql_union(THD *thd, LEX *lex, select_result *result,
   if (!(res= unit->prepare(thd, result, SELECT_NO_UNLOCK |
                            setup_tables_done_option)))
     res= unit->exec();
-  if (res || !thd->cursor || !thd->cursor->is_open())
-    res|= unit->cleanup();
+  res|= unit->cleanup();
   DBUG_RETURN(res);
 }