Get mobile app telemetry working again.

* run syslogd on gfrg200-family Network Boxes, using minijail to let it
  bind to the actual syslog port.
* advertise syslogd as a Zeroconf (Avahi) service on platforms where
  it runs.
* advertise isoping as a Zeroconf service, too.

This will let mobile devices on the local network find us to run
performance tests and upload results.

Change-Id: I4412575900b78242b9f2acbc6b2a7adb6413a8d2
11 files changed