Increase how long tests wait for server thread. (#746)
Increase how long tests wait for server thread. (#746)

Occasionally on circleci it takes longer than 1s to notice a thread has
exited, and with the existing socket timeout of 1s, it's possible for
this combined to exceed the current 2s join time. Increasing this to 5s
should cover all reasonable cases.
netsec-ethz/scion,dmpiergiacomo/scion,dmpiergiacomo/scion,netsec-ethz/scion,Oncilla/scion,klausman/scion,netsec-ethz/scion,netsec-ethz/scion,FR4NK-W/osourced-scion,FR4NK-W/osourced-scion,klausman/scion,Oncilla/scion,klausman/scion,dmpiergiacomo/scion,klausman/scion,dmpiergiacomo/scion,FR4NK-W/osourced-scion,dmpiergiacomo/scion,klausman/scion,Oncilla/scion,Oncilla/scion,FR4NK-W/osourced-scion,FR4NK-W/osourced-scion,dmpiergiacomo/scion