ec2test email summaries assume subunit output but allow submit output to be disabled

[Aaron Bentley]

ec2test email summaries assume the output contains subunit output. But if the user supplies -o options that don't include --subunit, subunit output will not be provided. It is unlikely that the user intends to disable subunit output, so --subunit should be prepended to -o options.

If there is a use case for disabling subunit output, this can be provided as a parameter to ec2test, e.g. "ec2 test --no-subunit", and this would disable prepending --subunit whether or not -o is supplied.

[Aaron Bentley (abentley)]

--no-subunit would also disable subunit-based summaries.

[Aaron Bentley (abentley)]

When subunit is disabled, email summaries make it look as if no tests were run, even though tests did run:

Tests started at approximately 2012-03-08 15:13:19.581565
Source: bzr+ssh://bazaar.launchpad.net/~abentley/launchpad/upgrade-all-2 r14078
Target: bzr+ssh://bazaar.launchpad.net/~launchpad-pqm/launchpad/devel/ r14922

0 tests run in 0:11:18.201887, 0 failures, 0 errors

(See the attached file for the complete log)