Allow sync-plan to change sync-date in WebUI
Cloned from https://bugzilla.redhat.com/show_bug.cgi?id=1177901
Description of problem:
Once I create a sync plan in Web UI, I can't change "Next Sync" / sync-date there. So I can't apply changes like "let synchronize with CDN at 3am, not at 5am every day".
As hammer CLI allows that change via sync-plan update --sync-date option, it is just WebUI lacking the ability to edit.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Create a sync plan via WebUI
2. Try to edit it.
You can change Name, Description and Interval, but not either Start Date or Next Sync.
You can change Name, Description, Interval and also Next Sync.
Once the Next Sync is changed, the next synchronization is really executed at that time and not at the original time.
Workaround: use hammer CLI.
Fixes #10140: allow sync plans start date to be editable, BZ 1177901.