Log Message:
-----------
Document that autovacuum_freeze_max_age is used for pg_clog recycling.
We already mentioned xid wraparound.
Modified Files:
--------------
pgsql/doc/src/sgml:
config.sgml (r1.305 -> r1.306)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/config.sgml?r1=1.305&r2=1.306)