SPINLOCK_BODY usage in OFI transport

[jdinan]

The usage of the SPINLOCK_BODY macro in the OFI put/get wait routines is a bit off-label for the x86 pause instruction. Probably harmless, but it might be a good idea to replace this with something else.

For reference: https://stackoverflow.com/questions/12894078/what-is-the-purpose-of-the-pause-instruction-in-x86