Revert r449826. There is no 4.02 release. Upon comparing the three tarballs
in my posession (4.00, 4.01 and 4.02), all three are the same.

The two emails received from portscout@FreeBSD.org on
portscout.ysv.freebsd.org on Wed, 13 Sep 2017 08:38:46 +0000 and
Thu, 14 Sep 2017 08:59:44 +0000 were incorrect.

Currently portscout reports at
https://portscout.freebsd.org/cy@freebsd.org.html
that the current release of xpdf4 is 4.10, which is obviously incorrect.

This commit also updates the MASTER_SITE to the new AWS location pointed
to by http://www.xpdfreader.com/.