test/smoke: panic on exit code but not exited
test/smoke: panic on exit code but not exited

- In theory this should never happen, but when running 80 tests
  concurrently (e.g. make test-smoke) I'm seeing various unexpected things
  happen occasionally.

samsalisbury/sous,samsalisbury/sous,samsalisbury/sous,opentable/sous,opentable/sous,samsalisbury/sous,opentable/sous,samsalisbury/sous,opentable/sous,opentable/sous