usnic: show the local UDP ports

[jsquyres]

Signed-off-by: Jeff Squyres [email protected]

[jsquyres]

@bturrubiates Please review.

This functionality came up the other day when helping debug some cluster-setup issues; we wanted to trace the traffic from one MPI process to another, but MPI processes didn't provide diag output indicating their source IP address and UDP port. This commit adds verbose output (when running with --mca btl_base_verbose) that shows both the local UDP ports, and also, when "connecting" to a remote peer, show both the local and remote IP/UDP ports. It's solely for diagnostic / verbose output purposes.

[jsquyres]

@bturrubiates actually recommends this kind of thing: https://gist.github.com/jsquyres/dd959a48b6d9d34a41261c7cf7998a5e

I don't have time to look at this at the moment, but wanted to stash it here so I don't lose it.

[jsquyres]

@bturrubiates Updated with your suggestion. Have a look.

[jsquyres]

@bturrubiates Got your latest feedback in this update.

[bturrubiates]

Looks good 👍

[jsquyres]

I'm not sure why the Mellanox Jenkins would timeout in its test; this PR only deals with code in the usnic BTL, which the Mellanox Jenkins does not test.