pg_dump dependency loop with extension containing its own schema

Hi,

I'm getting a dependency loop issue with pg_dump when adding a schema
to an extension where the schema being added is the same as the one
containing the extension.

CREATE EXTENSION file_fdw;
ALTER EXTENSION file_fdw ADD SCHEMA public;

$ pg_dump -f /dev/null test
pg_dump: [sorter] WARNING: could not resolve dependency loop among these items:
pg_dump: [sorter]   SCHEMA public  (ID 5 OID 2200)
pg_dump: [sorter]   EXTENSION file_fdw  (ID 170 OID 28912)

or

CREATE SCHEMA meow;
CREATE EXTENSION file_fdw WITH SCHEMA meow;
ALTER EXTENSION file_fdw ADD SCHEMA meow;

$ pg_dump -f /dev/null test
pg_dump: [sorter] WARNING: could not resolve dependency loop among these items:
pg_dump: [sorter]   SCHEMA meow  (ID 7 OID 28917)
pg_dump: [sorter]   EXTENSION file_fdw  (ID 171 OID 28918)

but not

CREATE SCHEMA meow;
CREATE EXTENSION file_fdw WITH SCHEMA meow;
ALTER EXTENSION file_fdw ADD SCHEMA public;

$ pg_dump -f /dev/null test3
$
(no errors shown)

I can produce this issue in 9.1.4 and head (as of commit
83af58f6b5657840f5924332fccecca1e3556abe).

Since this is a bug report, I'll include the necessary supporting info:
OS: Linux Mint x64
Kernel: 3.2.0-27-generic
CC version: Linaro 4.6.3-1ubuntu5
RAM: 16GB DDR3

--
Thom