Update PostgreSqlPlatform.php

If the database have different schemes, with objects, that the actual logged in user has no rights, the existing statements will collect all objects (sequences and tables) and try to read them in later steps. This will throws exceptions. The reason for that is the fact, that both procedures getListSequencesList() and getListTablesSQL() will receive all known database objects from postgres catalogs. But the actual logged-in user, maby has no read permissions to object inside other scheme-owner. The additional parts inside both sql-statements will reduce the result to only objects that the user are able to see.
Build broke because column reference needs to be `n.oid`.