In the ha_partition::position we don't calculate the number of
the partition of the record. We use m_last_part_value instead relying on
that it is set in other place like previous calls of ::write_row().
In replication we do neither of these calls before ::position().
Delete_row_log_event::do_exec_row calls find_and_fetch_row() where
we used position() & rnd_pos() calls to find the record for the
PARTITION/INNODB table as it posesses InnoDB table flags.
Fixed by removing HA_PRIMARY_KEY_REQUIRED_FOR_POSITION flag from PARTITION
