remove useless quote_ident
Merge pull request #2 from 3nids/schemasafe

`text || regclass`, via the `regclass` to `text` cast, already quotes table identifiers where necessary. The `quote_ident` calls here are unnecessary, and in fact incorrect as they result in quotes that were part of the table quoting becoming part of the identifier name.

Example:

```
create table "I will
hack your');DROP TABLE student;--" (
haha integer
);

SELECT '"I will
hack your'');DROP TABLE student;--"'::regclass::oid;

-- Produces oid 53060 here

regress=> SELECT 'DROP TABLE ' || 53060::oid::regclass;
              ?column?              
------------------------------------
 DROP TABLE "I will                +
 hack your');DROP TABLE student;--"
(1 row)

regress=> SELECT 'DROP TABLE ' || quote_ident(53060::oid::regclass::text);
               ?column?               
--------------------------------------
 DROP TABLE """I will                +
 hack your');DROP TABLE student;--"""
(1 row)
```