A number of CQ runs have failed in a distinct, apparently new
fashion.  Here's the most egregious example:
    https://uberchromegw.corp.google.com/i/chromeos/builders/master-paladin/builds/12355

Something around 8 of the paladins in that run failed with
the symptom.  The failure signature is this report in the HWTest
logs:
  <class 'urllib2.URLError'>(<urlopen error [Errno 110] Connection timed out>)

Different builders report different tracebacks.  In all
cases, the evidence is that the ultimate failure is that an
RPC call to cautotest was rejected with ECONNREFUSED.