ALTER TYPE COLLATABLE?

I observe the following discrepancy between the 9.0 and 9.1 citext
install scripts:

***************
*** 52,58 ****
STORAGE = extended,
-- make it a non-preferred member of string type category
CATEGORY = 'S',
! PREFERRED = false
);

--
--- 49,56 ----
STORAGE = extended,
-- make it a non-preferred member of string type category
CATEGORY = 'S',
! PREFERRED = false,
! COLLATABLE = true
);

--

What are we going to do to allow the citext update script to fix this?
I see no sign that ALTER TYPE can fix it (and am unsure that we'd want
to add such a feature, particularly not right now). Is it time for
a direct UPDATE on the pg_type row? If so, to what? I see
pg_type.typcollation is supposed to be an OID, so how the heck does
one map a bool CREATE TYPE parameter into the catalog entry?

regards, tom lane