Show schemas in information_schema.schemata that the current has access to

Before, it would only show schemas that the current user owns.  Per
discussion, the new behavior is more useful and consistent for PostgreSQL.

doc/src/sgml/information_schema.sgml

@@ -4547,8 +4547,9 @@ ORDER BY c.ordinal_position;
   <title><literal>schemata</literal></title>
 
   <para>
-   The view <literal>schemata</literal> contains all schemas in the
-   current database that are owned by a currently enabled role.
+   The view <literal>schemata</literal> contains all schemas in the current
+   database that the current user has access to (by way of being the owner or
+   having some privilege).
   </para>
 
   <table>

src/backend/catalog/information_schema.sql

@@ -1502,7 +1502,9 @@ CREATE VIEW schemata AS
            CAST(null AS sql_identifier) AS default_character_set_name,
            CAST(null AS character_data) AS sql_path
     FROM pg_namespace n, pg_authid u
-    WHERE n.nspowner = u.oid AND pg_has_role(n.nspowner, 'USAGE');
+    WHERE n.nspowner = u.oid
+          AND (pg_has_role(n.nspowner, 'USAGE')
+               OR has_schema_privilege(n.oid, 'CREATE, USAGE'));
 
 GRANT SELECT ON schemata TO PUBLIC;