sysutils/xmbmon: Primary Distribution Point Closure Response

As of December 15, 2025, Japan Standard Time, there is no response from
www.nt.phys.kyushu-u.ac.jp.
The site itself has recently moved, but since the source code does not
exist, a backup is stored in the je3kmz directory at freefall.freebsd.org.

While here replace PORTVERSION with DISTVERSION.

PR: 291678
(cherry picked from commit a62bbac9a5f70ad844f68664820d178c9623535f)