memory leaks with prepared statement cache (mariadb_c)

def test_bulk_delete(self):

        if is_maxscale():

            self.skipTest("MAXSCALE doesn't support BULK yet")

        with create_connection({"cache_prep_stmts" : True}) as connection:

            cursor = connection.cursor()

            cursor.execute("CREATE TEMPORARY TABLE bulk_delete ("

                           "id int, name varchar(64), city varchar(64))")

            params = [(1, u"Jack", u"Boston"),

                      (2, u"Martin", u"Ohio"),

                      (3, u"James", u"Washington"),

                      (4, u"Rasmus", u"Helsinki"),

                      (5, u"Andrey", u"Sofia")]

            cursor.executemany("INSERT INTO bulk_delete VALUES (?,?,?)", params)

            self.assertEqual(cursor.rowcount, 5)

            params = [(1,), (2,)]

            cursor.executemany("DELETE FROM bulk_delete WHERE id=?", params)

            self.assertEqual(cursor.rowcount, 2)

            cursor.close()

==16705== LEAK SUMMARY:

==16705==    definitely lost: 944 bytes in 1 blocks

==16705==    indirectly lost: 8,320 bytes in 4 blocks

==16705==      possibly lost: 172,711 bytes in 95 blocks

==16705==    still reachable: 1,172,125 bytes in 709 blocks

==16705==         suppressed: 0 bytes in 0 blocks