pgsql: Point to our download URL, rather than listing interface in the

Log Message:
-----------
Point to our download URL, rather than listing interface in the README
file:

http://www.postgresql.org/download

Modified Files:
--------------
pgsql:
README (r1.36 -> r1.37)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/README?r1=1.36&r2=1.37)