fixes #7343 / BZ 1132576 - iso sync - fix issue where progress report not available yet

This is to address the issue where 'task_progress_details' returned
nil due to the pulp response not yet containing the progress report.
Merge pull request #4639 from bbuckingham/issue-7343

fixes #7343 / BZ 1132576 - iso sync - fix issue where progress report not available yet