[autotest] log HQE status data to elasticsearch

HostQueueEntry will call set_status method everytime it change
status. We want to log the time it changes status in order
to measure overhead, i.e. how long it is resetting, starting,
verifying, parsing, etc.) Example metadata reported:
{
    'status': 'Parsing',
    'host_id': 1L,
    'hostname': u'172.22.169.106',
    'job_id': 6L,
    'time_changed': 1405359706.958406
}
BUG=None
TEST=Ran a reboot test and verified stats were in elasticsearch
Change-Id: I42ba6dca07e87084b57a6c47ed461c22307e7afe
Reviewed-on: https://chromium-review.googlesource.com/207812
Commit-Queue: Michael Liang <michaelliang@chromium.org>
Tested-by: Michael Liang <michaelliang@chromium.org>
Reviewed-by: Michael Liang <michaelliang@chromium.org>
Reviewed-by: Dan Shi <dshi@chromium.org>
1 file changed