BUG #13413: pg_stat_statements don't statistics "DEALLOCATE ALL" statements

The following bug has been logged on the website:

Bug reference:      13413
Logged by:          lidong.he
Email address:      held911@163.com
PostgreSQL version: 9.4.1
Operating system:   linux
Description:

this function is ok in pg 9.3.5.  But , it does not work in pg 9.4.1. it's
like follow:
b2c_product=# deallocate all;
DEALLOCATE ALL
b2c_product=# select query from pg_stat_statements where query ~*
'deallocate';
 query
-------
(0 rows)

b2c_product=# select query from pg_stat_activity where query ~* 'deallocate'
limit 2;
                                  query
-------------------------------------------------------------------------
 select query from pg_stat_activity where query ~* 'deallocate' limit 2;
  DEALLOCATE ALL;
(2 rows)