pgsql: Edit the SSL and Kerberos parts of the release notes a bit, and

Log Message:
-----------
Edit the SSL and Kerberos parts of the release notes a bit, and add
a note about the certificates chains patch just applied.

Modified Files:
--------------
pgsql/doc/src/sgml:
release-8.4.sgml (r1.1 -> r1.2)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/release-8.4.sgml?r1=1.1&r2=1.2)