[ewg] IB/ipoib: Fix neigh destructor oops for kernels older than 2.6.21

[Or Gerlitz]

Eli Cohen wrote:
> Good, so now we have some experience that it works and I don't see any
> comments on the patch itself. Unless there are objections I will push
> this to OFED as a backport for kernels <= 2.6.20.
>
Eli,

1 day is not enough time to review the patch, as of the importance, I 
suggest you ask Roland and Alexey to review it and say what their 
opinion on the solution, now once we all understand the problem.

Or.