Fixed memory leak in sql_parse.cc (lex_end() was not called)

This caused sp-vars.test to fail

sql/item_func.h

@@ -284,6 +284,7 @@ class Item_func_connection_id :public Item_int_func
   longlong value;
 
 public:
+  Item_func_connection_id() {}
   const char *func_name() const { return "connection_id"; }
   void fix_length_and_dec();
   bool fix_fields(THD *thd, Item **ref);

sql/sp.cc

@@ -269,7 +269,6 @@ db_find_routine_aux(THD *thd, int type, sp_name *name, TABLE *table)
 static int
 db_find_routine(THD *thd, int type, sp_name *name, sp_head **sphp)
 {
-  extern int MYSQLparse(void *thd);
   TABLE *table;
   const char *params, *returns, *body;
   int ret;
@@ -478,6 +477,7 @@ db_load_routine(THD *thd, int type, sp_name *name, sp_head **sphp,
     (*sphp)->optimize();
   }
 end:
+  lex_end(thd->lex);
   thd->spcont= old_spcont;
   thd->variables.sql_mode= old_sql_mode;
   thd->variables.select_limit= old_select_limit;

sql/sp_head.cc

@@ -671,6 +671,7 @@ sp_head::destroy()
   DBUG_ASSERT(m_lex.is_empty() || m_thd);
   while ((lex= (LEX *)m_lex.pop()))
   {
+    lex_end(m_thd->lex);
     delete m_thd->lex;
     m_thd->lex= lex;
   }
@@ -1643,7 +1644,10 @@ sp_head::restore_lex(THD *thd)
   */
   merge_table_list(thd, sublex->query_tables, sublex);
   if (! sublex->sp_lex_in_use)
+  {
+    lex_end(sublex);
     delete sublex;
+  }
   thd->lex= oldlex;
   DBUG_VOID_RETURN;
 }

sql/sp_head.h

@@ -520,7 +520,10 @@ public:
   virtual ~sp_lex_keeper()
   {
     if (m_lex_resp)
+    {
+      lex_end(m_lex);
       delete m_lex;
+    }
   }
 
   /*