pbulk with MAKE_JOBS

[klu <kludev%gmail.com@localhost>]

Where do I specify MAKE_JOBS for pbulk? There are two mk.config, one
in `/usr/pkg/etc`, another in `/usr/pbulk/etc`. I tried to put
MAKE_JOBS=2 in both, but seems I still get one CPU busy at a time.

Thanks!