"Start Revision" update of Perforce repo fails to prompt for a re-index on Save if the field was blank

Summary

Steps to Reproduce

1. Navigate to FishEye/Crucible Administration
2. Edit repository (cog > "View ..." OR select repository name) to reveal repository configuration screen modal
3. Select "SCM Details" tab
4. Update "Start Revision" field
5. Click "Save" button

Expected Results

Modal window "A reindex is required":

Actual Results

The repository configuration modal disappears.

Notes

If there is a value in the "Start Revision" field then the reindex modal is displayed correctly.

Workaround

Select the "Maintenance" tab on the repository configuration modal and select the "Start" button for "Re-index".