lib/modules: Re-implement queue_rw.go without depending on upcqueue.

I would like to move upcqueue back to internal.  I think the new implementation
is simpler and more correct.  The previous implementation had the rather
odd semantic that writing a zero-byte slice closed the queueRW.

Change-Id: Ie2e96dcca6b8c78afdb1cf9fc0fec958d8fd92c4
2 files changed