Http server throwing exceptions when viewing job files

[warownia1]

Possibly caused when retrieving output for a job that hasn't been initialized yet. Not critical as the exception is handled by werkzeug but results in an unpleasant 500 Internal Server Error. If that's the case, checking for nulls before creating a Job object is a solution.

File "slivka/server/api_views.py", line 172, in job_files_view
    job = req.job
File "slivka/db/documents.py", line 124, in _get_job
    def _get_job(self): return JobRequest.Job(**self['job'])
TypeError: type object argument after ** must be a mapping, not NoneType