Fix exception when user is created w/o a group.
Fix exception when user is created w/o a group.

https://bugzilla.redhat.com/show_bug.cgi?id=1127093
(transferred from ManageIQ/manageiq@65cddb294e41e0b49ea20f57f456ad563ba19b42)

ManageIQ/manageiq-ui-classic,ManageIQ/manageiq-ui-classic,ManageIQ/manageiq-ui-classic,ManageIQ/manageiq-ui-classic