Thread: pgsql: Update copyright information in documentation.

Log Message:
-----------
Update copyright information in documentation. Also, add a note
to RELEASE_CHANGES so that this is not forgotten in the future.

Modified Files:
--------------
    pgsql/doc/src/sgml:
        legal.sgml (r1.16 -> r1.17)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/legal.sgml.diff?r1=1.16&r2=1.17)
    pgsql/src/tools:
        RELEASE_CHANGES (r1.47 -> r1.48)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/tools/RELEASE_CHANGES.diff?r1=1.47&r2=1.48)