[ofiwg] libfabric v1.7.0rc3 now available

[Hefty, Sean]

> Known issues have been resolved.  Barring any new bug discoveries, the final
> release is targeted for next week.

There were several fixes to the rxd provider since rc2, plus fixes applied to the core and rxm provider.  As a result, I'm creating an rc3: 

https://github.com/ofiwg/libfabric/releases/tag/v1.7.0rc3

There is one minor fix to usnic that is still pending (may not be needed for 1.7), plus one unresolved issue that shows up running RMA bandwidth tests over RxD + hfi1 verbs.  Final release for 1.7 is now targeting the first half of January, unless other issues crop up.

- Sean