pgsql: Update PITR TODO items: < failure.

Log Message:
-----------
Update PITR TODO items:

< failure.

failure. This could be triggered by a user command or a timer.

< * Force archiving of partially-full WAL files when pg_stop_backup() is
< called or the server is stopped

* Automatically force archiving of partially-filled WAL files when
pg_stop_backup() is called or the server is stopped

Modified Files:
--------------
pgsql/doc:
TODO (r1.1495 -> r1.1496)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/TODO.diff?r1=1.1495&amp;r2=1.1496)