Petitboot v1.7.2 tagged

[Samuel Mendoza-Jonas]

Petitboot v1.7.2 has been released. This patch version includes the
following fixes:

- Some improvements to Petitboot logging to aid debugging.

- A backport of the network re-query feature introduced by
  6fa0edf "discover: implement a periodic requery for network devices"

These help bring some resilience against unreliable networks to users on
the v1.7.x stream, which for ppc64le at least is most of them.