BUG #7515: DROP TABLE IF EXISTS fails if schema does not exist

The following bug has been logged on the website:

Bug reference: 7515
Logged by: James Bellinger
Email address: james(at)illusorystudios(dot)com
PostgreSQL version: 9.1.5
Operating system: Ubuntu Linux 12.04 Server
Description:

If the table being referenced has a schema in its name, and the schema does
not exist, DROP TABLE IF EXISTS will have an ERROR instead of a NOTICE.

So for instance,
DROP TABLE IF EXISTS bar;
This is a NOTICE if bar does not exist.

DROP TABLE IF EXISTS foo.bar;
This is an ERROR if foo does not exist, even though that implies bar does
not exist which means it should be a NOTICE.

Saw this because it was making a drop/recreate transaction fail on me, after
I changed some code to use a schema.