Fix for memory leak which was introduced by patch improving locking in SP.

Made mysql_make_view() to call destructor for st_lex_local objects before
throwing them away (this happens in case of error).


sql/sql_lex.h:
  Made LEX's destructor virtual to be able properly destroy objects
  of inherited classes (i.e. of st_lex_local).
sql/sql_view.cc:
  mysql_make_view():
    We should call destructor for st_lex_local object before throwing
    it away.

sql/sql_lex.h

@@ -816,8 +816,8 @@ typedef struct st_lex
     hash_init(&spfuns, system_charset_info, 0, 0, 0, sp_lex_sp_key, 0, 0);
     hash_init(&spprocs, system_charset_info, 0, 0, 0, sp_lex_sp_key, 0, 0);
   }
-  
-  ~st_lex()
+
+  virtual ~st_lex()
   {
     hash_free(&spfuns);
     hash_free(&spprocs);