usnic_channel_finalize() was deregistering recv buffers before
destroying the QP to which they were posted. The QP needs to be
destroyed first so that the NIC does not attemp tto write to
deregistered memory, causing the DMAR messages.
Submitted by Reese, reviewed by Jeff.
cmr=v1.7.4:reviewer=ompi-rm1.7
This commit was SVN r29963.