Set PathPolicy defaults to saner values. (#1741)
Set PathPolicy defaults to saner values. (#1741)

- Accept any PCB that's <= 4 hours old (increased from 60s)
- Allow segments with 30 hops (increased from 10), as the core in the
  beginning may not be very tightly meshed.
klausman/scion,netsec-ethz/scion,klausman/scion,klausman/scion,Oncilla/scion,Oncilla/scion,netsec-ethz/scion,Oncilla/scion,klausman/scion,netsec-ethz/scion,klausman/scion,netsec-ethz/scion,Oncilla/scion