Created attachment 1546051 [details]
Step 4 and also the actual result after step 5

Description of problem:
Cannot create a group for the second time, after displaying a validation message 'Description is not unique within region 0'.

Version-Release number of selected component (if applicable):
latest 5.9, also 5.10

How reproducible:
always

Steps to Reproduce:
1. Go to Configuration > Access Control > Groups accordion
2. Configuration > Add a new Group, create a group
3. Try to create another group with the same description as from step 2
   => error flash message occurs
4.Follow the message and change the description of the new group to be unique, 5. Press Add button

Actual results:
Nothing happens in the UI, the page remains the same, error:

[----] I, [2019-03-19T17:28:55.994747 #11522:2ad94de6c2f0]  INFO -- : Started POST "/ops/rbac_group_edit?button=add" for ::1 at 2019-03-19 17:28:55 +0100
[----] I, [2019-03-19T17:28:56.033217 #11522:2ad94de6c2f0]  INFO -- : Processing by OpsController#rbac_group_edit as JS
[----] I, [2019-03-19T17:28:56.033346 #11522:2ad94de6c2f0]  INFO -- :   Parameters: {"button"=>"add"}
[----] F, [2019-03-19T17:28:56.045202 #11522:2ad94de6c2f0] FATAL -- : Error caught: [NoMethodError] undefined method `empty?' for nil:NilClass
/home/hstastna/manageiq/manageiq-ui-classic/app/controllers/ops_controller/ops_rbac.rb:1377:in `rbac_group_validate?'
/home/hstastna/manageiq/manageiq-ui-classic/app/controllers/ops_controller/ops_rbac.rb:674:in `rbac_edit_save_or_add'
/home/hstastna/manageiq/manageiq-ui-classic/app/controllers/ops_controller/ops_rbac.rb:92:in `rbac_group_edit'

Expected results:
Group should be saved with no problems, after changing the description to be different to the already existing groups' descriptions, flash message about success should appear.

Additional info: