classes/tinderclient.bbclass: Add workaround for bitbake -k and save the status

classes/tinderclient.bbclass: Add workaround for bitbake -k and save the status
    Using the continue option of BitBake can lead to some issues with the
    Tinderbox. Even if one build failed the color of the result will be green
    as the BuildCompleted event will be send by BitBake.
    As a workaround we will store the failure in a tinder-status file in case
    of failure (e.g. no Provider or PkgFailed) and will reread on the start.
    When the build starts we will truncate the file and remove 'the' error