Description of problem:
[RFE] Create Sync Plan Interval is pre-selected as "hourly" input value

Version-Release number of selected component (if applicable):
Satellite 7.0

How reproducible:

Steps to Reproduce:
1. Login to Satellite Web UI -> Content -> Sync Plan
2. Create Sync Plan -> pre-selected Interval: hourly

Actual results:
Interval input is pre-selected as hourly input

Expected results:
Interval input should be blank, so that users can select

Additional info:
Sometime pre-selected inputs are consider as recommended