Make /contrib install/uninstall script consistent:

remove transactions
	use create or replace function
	make formatting consistent
	set search patch on first line

Add documentation on modifying *.sql to set the search patch, and
mention that major upgrades should still run the installation scripts.

Some of these issues were spotted by Tom today.

contrib/lo/lo.sql.in

@@ -1,9 +1,3 @@
---
---	PostgreSQL code for managed Large Objects
---
---	$PostgreSQL: pgsql/contrib/lo/lo.sql.in,v 1.13 2005/06/23 00:06:37 tgl Exp $
---
-
 -- Adjust this setting to control where the objects get created.
 SET search_path = public;
 
@@ -19,11 +13,11 @@ CREATE DOMAIN lo AS pg_catalog.oid;
 -- The other functions that formerly existed are not needed because
 -- the implicit casts between a domain and its underlying type handle them.
 --
-CREATE FUNCTION lo_oid(lo) RETURNS pg_catalog.oid AS
+CREATE OR REPLACE FUNCTION lo_oid(lo) RETURNS pg_catalog.oid AS
 'SELECT $1::pg_catalog.oid' LANGUAGE SQL STRICT IMMUTABLE;
 
 -- This is used in triggers
-CREATE FUNCTION lo_manage()
+CREATE OR REPLACE FUNCTION lo_manage()
 RETURNS pg_catalog.trigger
 AS 'MODULE_PATHNAME'
 LANGUAGE C;

contrib/lo/lo_test.sql

@@ -1,3 +1,6 @@
+-- Adjust this setting to control where the objects get created.
+SET search_path = public;
+
 --
 -- This runs some common tests against the type
 --

contrib/lo/uninstall_lo.sql

@@ -1,11 +1,11 @@
+-- Adjust this setting to control where the objects get dropped.
+SET search_path = public;
+
 --
 -- This removes the LO type
 -- It's used just for development
 --
 
--- Adjust this setting to control where the objects get created.
-SET search_path = public;
-
 -- drop the type and associated functions
 DROP TYPE lo CASCADE;