[Server process manager] do NOT delete process files if exit code is not 0 for OTHER THAN MRI_Upload

[cmadjar]

Based on the Loris Pull request meeting of Oct'14, 2016:

PR (#2252) has been merged, but Dave thinks that any process (not just the MRI Upload) that runs the server_process_manager should keep the files if exit code is not 0 (please see comments on the pull request).
Decision was to merge the pull request as currently only imaging uploader uses this module, but in the future when more modules use it, debugging files should be kept as well.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.