pgsql: incorrect parameter replacement in metaColumns()

[dregad]

Regression introduced in 5.20.0 by f54e496

When the _generateMetaColumnsSQL() protected method was introduced, the original sprintf() statement was not correctly copied into the new function:

// The original code in MetaColumns() function
-sprintf($this->metaColumnsSQL,$table,$table,$table)
// became this in _generateMetaColumnsSQL()
+sprintf($this->metaColumnsSQL, $table, $table, $schema)

This causes an incorrect where clause to be applied to the query (the table name is compared to the lowercase schema name).

Will be fixed as part of PostgreSQL driver refactoring #955.