report and record the actual booted kernel with test results

As discussed on IRC, we want something like this for 2:

>>> print(json.dumps({'kernel_version': '1.2', 'test_kernel_versions': [('test2', 'reboot_to_backport', '1.3~utopic')]}, indent=2))
{
  "kernel_version": "1.2",
  "test_kernel_versions": [
    [
      "test2",
      "reboot_to_backport",
      "1.3~utopic"
    ]
  ]
}

kernel_version is the version right after the initial testbed setup/dist-upgrade/reboot. Any test which triggers a reboot which ends up in a kernel != kernel_version will get an entry in that test_kernel_versions list. Any test/reboot which is not there can be assumed to use kernel_version. IOW, for pretty much all expected cases test_kernel_versions should be completely absent.

We use json instead of yaml as the latter requires an external Python module.

test_kernel_versions → kernel_version_changes

Also add the test triggers into that json file.

Kernel is logged with http://anonscm.debian.org/cgit/autopkgtest/autopkgtest.git/commit/?id=b0dd5d5c59 (rolled out to all runners)

This is implemented in http://anonscm.debian.org/cgit/autopkgtest/autopkgtest.git/commit/?id=f5e719a4 now.
This needs some additional changes in autopkgtest-cloud to put the new file into result.tar.

With https://git.launchpad.net/~ubuntu-release/+git/autopkgtest-cloud/commit/?id=64b1862d1 this should now be live.

Pulled for now, causes

https://objectstorage.prodstack4-5.canonical.com/v1/AUTH_77e2ada1e7a84929a74ba3b87153c0ac/autopkgtest-trusty/trusty/i386/o/open-iscsi/20150911_152523@/log.gz

Fixed harder in http://anonscm.debian.org/cgit/autopkgtest/autopkgtest.git/commit/?id=1ecab4be6 and rolled out. Seems to be working alright so far, e. g. https://objectstorage.prodstack4-5.canonical.com/v1/AUTH_77e2ada1e7a84929a74ba3b87153c0ac/autopkgtest-wily/wily/i386/liba/libaws/20150914_092637%40/result.tar

With http://anonscm.debian.org/cgit/autopkgtest/autopkgtest.git/commit/?id=b5963450b the triggers are now exposed in testinfo.json. As autopkgtest itself doesn't have a concept of "test trigger" this isn't a separate key, but it will be an ADT_TEST_TRIGGERS=srcpkgname entry in the "custom_environment" entry of testinfo.json.

This bug was fixed in the package autopkgtest - 3.17.1

---------------
autopkgtest (3.17.1) unstable; urgency=medium

  * Add new private python modules to Makefile, to actually ship them.
  * tests/adt-run: Fix test regression when $ADT_TEST* are not set.

 -- Martin Pitt <email address hidden> Tue, 15 Sep 2015 08:38:54 +0200