Use current postgresql schema instead of hardcoded "public".

Under postgresql, in case of altered default search_path for drupal account (mean if you don't work in default public schema). ex:

alter database db set search_path drupal,public; or alter user drupal set search_path to drupal,public;

installation fails with a mysterious AJAX ERROR and SQLSTATE[25P02].

function queryTableInformation (includes/database/pgsql/schema.inc) is at origin of that by requesting schema information for table in postgresql schema 'public' by default.

This can be avoided by prefixing at install with the new default schema (dot must be appended).

Another more transparent solution could be to patch using postgresql function current_schema() instead.