No FI_EBUSY error for GNI provider

[dschraufna]

When attempting to close an Address Vector that is still bound to an Endpoint, a -FI_EBUSY error should be returned. In the case of the GNI provider, no such error is returned; the return value is 0.
A -FI_EBUSY signal is properly returned for the sockets provider.

Man page reference: https://ofiwg.github.io/libfabric/v1.4.1/man/fi_av.3.html#fi_close

Rough code outline:

fi_av_open(domain, &av_attr, &target_av, NULL);
fi_ep_bind(endpoint, &target_av->fid, 0);
ret = fi_close(&target_av->fid);
if (ret != -FI_EBUSY) { 
   //We failed to get the expected error
   printf("%d\n", ret); //Returns 0 in the case of GNI provider 
} else { 
   //We received FI_EBUSY signal. Tests passes.
}

Let me know if I can provide any additional info.