Log Message:
-----------
Add mention of shared-memory/disk for multi-master clustering.
Modified Files:
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pgsql/doc/src/sgml:
high-availability.sgml (r1.8 -> r1.9)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/high-availability.sgml.diff?r1=1.8&r2=1.9)