Merge pull request #285 from venkateshsampath/pep8/E501

Fix PEP8 issue: E501 line too long
Merge pull request #284 from venkateshsampath/rm5237

Fix the unit test failing because of 'iso8601' version upgrade.
Merge pull request #282 from venkateshsampath/rm/4826

make qonos migration's db_version work similar to nova
implement 'qonos.job.failed' notification.

This patch includes the following changes:
- introduce a new notification event called 'qonos.job.failed' for final
  job failure.
- add a notification event for intermittent job failures using
  'qonos.job.update' with severity level set to ERROR
- send job info as payload with the notification.
- refactor process_job() method catch Polling and any other Exception and
  handle them by updating the job status as 'ERROR' and send
'qonos.job.failed' notification for the failed job.

Related to RM 4647

Co-authored-by: Sridevi Koushik <sridevi.koushik@rackspace.com>