update bsd.sites.mk - add mozdev mirrors

Add http://mozdev.org/ mirrors
Source: http://www.mozdev.org/docs/download.html
(with some corrections)
Justification: 7 ports can use these mirrors, 2 more
are coming (conkeror, linux-conkeror), many more will
need it as our xpi infrastructure is developing

PR: ports/96418
Submitted by: Andrew Pantyukhin <infofarmer@gmail.com>