hanging build job prevents new jobs to be started for that project

[tpokorra]

happens for kolab test on Ubuntu xenial.

in database:

MariaDB [lbs]> select * from build where finished = 0 and status != 'CANCELLED' limit 30;
+-------+----------+-----------+-------------+-------------+-----------------+--------+---------+-------+----------+-------------+------------------------+------------------------------------+---------------------+---------------------+---------+--------------+-------------+
| id    | status   | username  | projectname | packagename | branchname      | distro | release | arch  | avoidlxc | avoiddocker | dependsOnOtherProjects | buildmachine                       | started             | finished            | hanging | buildsuccess | buildnumber |
+-------+----------+-----------+-------------+-------------+-----------------+--------+---------+-------+----------+-------------+------------------------+------------------------------------+---------------------+---------------------+---------+--------------+-------------+
| 12714 | BUILDING | tbits.net | kolab-test  | kolab-test  | Kolab16         | ubuntu | xenial  | amd64 |        0 |           1 | kolab-nightly          | build04lxc.lbs.solidcharity.com    | 2017-05-10 16:23:11 | 0000-00-00 00:00:00 |       1 | NULL         |        NULL |

When I want to start the job, it displays the log of the hanging job

[tpokorra]

seems in LightBuildServer.py, CheckForHangingBuild, does not work:

      # when the build job realizes that the buildmachine is gone:
      #   the log will be written, email sent, and logs cleared
      #   the build will be marked as failed as well