Fixed KeyError crash in mailer.py

Fixed KeyError crash in mailer.py

Looks like event, which comes from obs plugin doesn't have
'origintype' field.

====Notify the tag owner====================================
Traceback (most recent call last):
  File "/srv/jenkins/jenkins-scripts/job_request.py", line 315, in <module>
    sys.exit(main())
  File "/srv/jenkins/jenkins-scripts/job_request.py", line 282, in main
    notify_submiter(event_fields, data)
  File "/srv/jenkins/jenkins-scripts/job_request.py", line 261, in notify_submiter
    os.getenv('EMAIL_TEMPLATES_DIR'))
  File "/srv/jenkins/jenkins-scripts/requests/mailer.py", line 238, in mailer
    if not tri['cond'] or tri['cond'](_bs, request):
  File "/srv/jenkins/jenkins-scripts/requests/mailer.py", line 58, in <lambda>
    'cond':  lambda bs, req: req['origintype'] == 'change_devel',
KeyError: 'origintype'

Change-Id: I28f3866c3b37b7782576c9e613c8904050053526