Log Message:
-----------
Add "Communication Method" row to HA feature matrix documentation.
Modified Files:
--------------
pgsql/doc/src/sgml:
high-availability.sgml (r1.30 -> r1.31)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/high-availability.sgml?r1=1.30&r2=1.31)