Remove job_exec_data argument

The job_exec_data field was added to handle diverging schemas
for job executions.  With the addition of "edp." config settings
to handle job-type-specific data fields, this argument is no
longer needed.

Change-Id: I3ec277b6b407aa01784d4303bfa409dafdcbdeeb
Partial-implements: blueprint edp-config-parameter-prefix
Merge "Remove job_exec_data argument"