[ticket/12846] SQLite3 bug in profilefield_base_migration.php

Using profilefield_base_migration.php to create a custom profile
field with SQlite3 DBMS returns warning:

[phpBB Debug] PHP Warning: in file [ROOT]/phpbb/db/driver/sqlite3.php
on line 218: SQLite3Result::fetchArray(): Unable to execute statement:
constraint failed

This is due passing filed_id and lang_id to the DB driver in
unspecified format. As they are always int we should cast them
in int to prevent the error message appearance.

PHPBB3-12846