Fix displaying user detail page

[ZitaNemeckova]

Configuration -> Access Control -> Select User that has no Groups
Before:

F, [2018-04-04T16:52:35.609332 #65220] FATAL -- : Error caught: [ActionView::Template::Error] undefined method `[]' for nil:NilClass
/Users/zita/Desktop/ManageIQ/manageiq-ui-classic/app/views/ops/_rbac_user_details.html.haml:134:in `___sers_zita__esktop__anage___manageiq_ui_classic_app_views_ops__rbac_user_details_html_haml___1940073322298559570_70282346906420'
/usr/local/lib/ruby/gems/2.3.0/gems/actionview-5.0.7/lib/action_view/template.rb:159:in `block in render'
/usr/local/lib/ruby/gems/2.3.0/gems/activesupport-5.0.7/lib/active_support/notifications.rb:166:in `instrument'
/usr/local/lib/ruby/gems/2.3.0/gems/actionview-5.0.7/lib/action_view/template.rb:354:in `instrument'
/usr/local/lib/ruby/gems/2.3.0/gems/actionview-5.0.7/lib/action_view/template.rb:157:in `render'

After:
It works

@miq-bot add_label bug, gaprindashvili/yes

[miq-bot]

Checked commit ZitaNemeckova@1f129c2 with ruby 2.3.3, rubocop 0.52.1, haml-lint 0.20.0, and yamllint 1.10.0
1 file checked, 1 offense detected

**

• 💣 💥 🔥 🚒 - Linter/Haml - Linter::Haml STDERR:

warning: parser/current is loading parser/ruby23, which recognizes
warning: 2.3.6-compliant syntax, but you are running 2.3.3.
warning: please see https://github.com/whitequark/parser#compatibility-with-ruby-mri.

[mzazrivec]

@ZitaNemeckova How do I go about creating a user without a group?

[ZitaNemeckova]

@mzazrivec I think you shouldn't. I got few when I was working on #3714 and started to see error in description. So removing groups via console should work for testing it.

It's "just in case" fix. Pretty much prevents to go to else branch that looks at @edit because groups == [].