Log Message:
-----------
Remove 9.0 release notes xref's to HISTORY.html can be built.
Document this restriction.
Modified Files:
--------------
pgsql/doc/src/sgml:
release-9.0.sgml (r2.7 -> r2.8)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/release-9.0.sgml?r1=2.7&r2=2.8)
release.sgml (r1.637 -> r1.638)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/release.sgml?r1=1.637&r2=1.638)