Testrunner subprocess death unheeded by parent

[William Grant]

As seen in <https://lpbuildbot.canonical.com/builders/lucid_lp/builds/1335/steps/shell_6/logs/stdio> (sometimes hangs, try adding random query strings to get it to not hang), some testrunner subprocess failures are not handled correctly by the master process. In this case test_import_bzr (now disabled) caused the testrunner to hang and be killed. The master said:

**********************************************************************
Could not communicate with subprocess
**********************************************************************

but then continued on to say

Total: 15537 tests, 0 failures, 0 errors in 246 minutes 57.383 seconds.

Successfully ran all tests.
program finished with exit code 0

[William Grant (wgrant)]

Log saved at <https://devpad.canonical.com/~wgrant/2011/lucid_lp-1335-stdio>, as buildbot likes to prune.

[Colin Watson (cjwatson)]

This was fixed in zope.testrunner 4.4.0 (https://github.com/zopefoundation/zope.testrunner/issues/5), so we'll pick that up when we finally upgrade.

[Colin Watson (cjwatson)]

Fixed by https://code.launchpad.net/~cjwatson/launchpad/+git/launchpad/+merge/374387.