nvmf/rdma host crash during heavy load and keep alive recovery

[Steve Wise]

> 
> >> Can you also give patch [1] a try? It's not a solution, but I want
> >> to see if it hides the problem...
> >>
> >
> > hmm.  I ran the experiment once with [1] and it didn't crash.  I ran it a
2nd
> > time and hit a new crash.  Maybe a problem with [1]?
> 
> Strange, I don't see how we can visit rdma_destroy_qp twice given
> that we have NVME_RDMA_IB_QUEUE_ALLOCATED bit protecting it.
> 
> Not sure if it fixes anything, but we probably need it regardless, can
> you give another go with this on top:

Still hit it with this on top (had to tweak the patch a little).

Steve.