Log Message:
-----------
Update docs that GNU tar versions >=1.16 exit with 1 on files changed, 2
on other errors.
Modified Files:
--------------
pgsql/doc/src/sgml:
backup.sgml (r2.98 -> r2.99)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/backup.sgml.diff?r1=2.98&r2=2.99)