pgsql: Fix erroneous handling of shared dependencies (ie dependencies on

Log Message:
-----------
Fix erroneous handling of shared dependencies (ie dependencies on roles)
in CREATE OR REPLACE FUNCTION. The original code would update pg_shdepend
as if a new function was being created, even if it wasn't, with two bad
consequences: pg_shdepend might record the wrong owner for the function,
and any dependencies for roles mentioned in the function's ACL would be lost.
The fix is very easy: just don't touch pg_shdepend at all when doing a
function replacement.

Also update the CREATE FUNCTION reference page, which never explained
exactly what changes and doesn't change in a function replacement.
In passing, fix the CREATE VIEW reference page similarly; there's no
code bug there, but the docs didn't say what happens.

Tags:
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REL8_1_STABLE

Modified Files:
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pgsql/doc/src/sgml/ref:
create_function.sgml (r1.67.2.2 -> r1.67.2.3)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_function.sgml?r1=1.67.2.2&r2=1.67.2.3)
create_view.sgml (r1.31 -> r1.31.2.1)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_view.sgml?r1=1.31&r2=1.31.2.1)
pgsql/src/backend/catalog:
pg_proc.c (r1.135.2.1 -> r1.135.2.2)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/catalog/pg_proc.c?r1=1.135.2.1&r2=1.135.2.2)