temp tables should not have pg_shdepend entries

Among the consequences of creating a temp table is the fact that we
create pg_shdepend entries for the owner.  This is largely unnecessary
-- we only need it when the table owner is not the authenticated user.
I hereby propose we don't create those entries, since obviously the
tables would go away as soon as the connection goes away anyway, and the
user cannot go away until the connection does.

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support