I have the same problem, however I installed the Lustre kernel (Lustre 2.1, kernel 2.6.32-358.11.1.el6_lustre.x86_64). Did you find the solution?
As a first thought, are you sure you need the Mellanox OFED stack?
The yum "Infiniband Support" group included with standard RHEL 6.4 should "just work":
$ sudo yum groupinstall "Infiniband Support"
Apparently it's not as optimised for stuff as Mellanox OFED, but if you just need something that works "right out of the box" it's a good option.
Hopefully that's useful info.
(note - edited for minor clarification fixes)
IB software from RedHat is not a solution here. It will work but I didn't allow me to compile the proper MvAPICH library version.
I know that this might be a litttle bit more work for Mellanox but seems like releasing the new package suited for updated RHEL kernels is the solution.
No worres, it was a thought.
And yeah, the "proper" solution here will probably be in form of updated Mellanox OFED stack or similar.