[ofiwg] completion flags as actually defined by OFI

[Hefty, Sean]

> Perhaps all we can do at this point is recognize that new completions may
> be necessary and we allocate spare bits for them?

I think this is the real requirement that needs to be met.  OFI has this ability.

I am removing FI_COMMIT_COMPLETE from the API until things can be resolved.  I think this goes beyond a completion flag and may require changes to memory registration and/or a new operation.