pgsql: Restrict pgrowlocks function to superusers.

Log Message:
-----------
Restrict pgrowlocks function to superusers.  (This might be too strict,
but no permissions check at all is certainly no good.)  Clean up usage
of some deprecated APIs.

Modified Files:
--------------
    pgsql/contrib/pgrowlocks:
        README.pgrowlocks (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/pgrowlocks/README.pgrowlocks?r1=1.1&r2=1.2)
        pgrowlocks.c (r1.5 -> r1.6)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/pgrowlocks/pgrowlocks.c?r1=1.5&r2=1.6)
        pgrowlocks.sql.in (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/pgrowlocks/pgrowlocks.sql.in?r1=1.1&r2=1.2)
        uninstall_pgrowlocks.sql (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/pgrowlocks/uninstall_pgrowlocks.sql?r1=1.1&r2=1.2)