ports/89281: bsd.port.mk: Use portsnap on "make update"

[Mark Linimon]

Old Synopsis: Use portsnap on "make update"
New Synopsis: bsd.port.mk: Use portsnap on "make update"

Responsible-Changed-From-To: freebsd-ports-bugs->portmgr
Responsible-Changed-By: linimon
Responsible-Changed-When: Sat Nov 19 18:18:19 GMT 2005
Responsible-Changed-Why: 
Over to maintainer(s).

Note: this is a slight superset of the patch in ports/89197.

http://www.freebsd.org/cgi/query-pr.cgi?pr=89281