pgsql: Document method of removing invalid UTF8 escape sequences from

Log Message:
-----------
Document method of removing invalid UTF8 escape sequences from dump
file. Backpatch to 8.1.X.

Paul Lindner

Modified Files:
--------------
pgsql/doc/src/sgml:
release.sgml (r1.403 -> r1.404)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/release.sgml.diff?r1=1.403&r2=1.404)