[ofiwg] Travis CI testing of libfabric and fabtests

[Hefty, Sean]

> I've also enabled branch protection to the upstream trees.  Now that
> Travis CI is working, I'd like to propose that we require status checks to
> pass before pull requests can be merged.  The only drawback that I see to
> this is that there will be a small delay (~5-10 minutes) before simple
> pull requests can be merged.

In order to build other providers, we have dependencies on external libraries.  We need to determine how we want to handle that.  For example, do we pull a specific version, use only what's available through the build system, or pull directly from upstream git trees?  We probably need some combination of these.

Pulling upstream git trees where reasonable allows us to stay current, but does open the possibility that status checks could fail because of a problem in the upstream code.  The benefits of forcing status checks still seem to outweigh the risks, but we need a general policy of how to handle external libraries.

- Sean