Make batsched works when some jobs are not providing a walltime
Here is the error given by walltime test from 30-make-the-job-walltime-optional
branch:
9: 2017-09-28 08:11:25,410 0a2daad974a1 execute_one_instance[22791] ERROR Sched stderr:
9: Assertion 'object.HasMember("walltime")' failed (ERROR)
9: in file json_workload.cpp, line 128
9: function: Job *Workload::job_from_json_object(const Value &)
9: with message: Invalid json object: no 'walltime' member