request expired being raised does not increase the opstats timeout count

Failure in test lib/canonical/launchpad/pagetests/standalone/xx-opstats.txt
Traceback (most recent call last):
  File "/usr/lib/python2.6/unittest.py", line 279, in run
    testMethod()
  File "/usr/lib/python2.6/doctest.py", line 2152, in runTest
    raise self.failureException(self.format_failure(new.getvalue()))
AssertionError: Failed doctest test for xx-opstats.txt
  File "lib/canonical/launchpad/pagetests/standalone/xx-opstats.txt", line 0

----------------------------------------------------------------------
File "lib/canonical/launchpad/pagetests/standalone/xx-opstats.txt", line 183, in xx-opstats.txt
Failed example:
    report()
Differences (ndiff with -expected +actual):
      503s: 1
      5XXs: 1
      http requests: 1
      requests: 1
    - timeouts: 1

This occurs if the timeout tracer starts raising RequestExpired rather than TimeoutError, because the *tracer* does the opstats incrementing, rather than publication machinery.

I'm fixing this specific example by catching both exceptions, but other timeouts like the google search service timeout are probably not being recorded accurately.