Description of problem:
In WebUI tables for "Allowed for retrieve/create keytab" user/host/hostgroups/usergroups on service details page are shown as read-only - it is not possible to add anything. This state is there until the first user/usergroup/host/hostgroup is added over CLI. Then tables become writable. 

Before adding user/usergroup/host/hostgroup in CLI the API response does not contain 'ipaallowedtoperform' in attributelevelrights at all. After that the attribute level right is added into response and WebUI is shown correctly. 


Version-Release number of selected component (if applicable):
ipa-4.5.0-21.el7_4.1

How reproducible:
Always

Steps to Reproduce:
1. Install ipa server
2. Go to WebUI Identity - Services
3. Choose any service
4. Scroll down to 'Allow to retrieve/create keytab'
5. It is not possible to add any user/usergroup/host/hostgroup
6. Open command line and add a user to the particular service
$ ipa service-allow-create-keytab
7. Go back to WebUI 
8. Add button is now not grayed out

Actual results:
step 5

Expected results:
It should be possible to add user/usergroup/host/hostgroup right away, not only after first add.

Additional info: