Description of problem:
Configure Satellite 6 with LDAP with param "--ldap-server-type=free_ipa".
Add some LDAP group into user role, you will see the error:
"undefined method `empty?' for false:FalseClass".

Version-Release number of selected component (if applicable):
ruby193-rubygem-foreman-katello-engine-0.0.8-4.el6sat.noarch
ruby193-rubygem-katello_api-0.0.3-2.el6_4.noarch
katello-common-1.4.2-8.el6sat.noarch
katello-glue-elasticsearch-1.4.2-8.el6sat.noarch
katello-candlepin-cert-key-pair-1.0-1.noarch
katello-agent-1.4.2-4.el6sat.noarch
katello-qpid-broker-key-pair-1.0-1.noarch
katello-cli-1.4.2-6.el6sat.noarch
katello-configure-1.4.3-12.el6sat.noarch
signo-katello-0.0.15-1.el6sat.noarch
katello-glue-candlepin-1.4.2-8.el6sat.noarch
katello-selinux-1.4.3-3.el6sat.noarch
katello-1.4.2-8.el6sat.noarch
katello-configure-foreman-1.4.3-12.el6sat.noarch
katello-foreman-all-1.4.2-8.el6sat.noarch
katello-cli-common-1.4.2-6.el6sat.noarch
katello-certs-tools-1.4.2-2.el6sat.noarch
katello-glue-pulp-1.4.2-8.el6sat.noarch
ruby193-rubygem-katello-foreman-engine-0.0.3-4.el6sat.noarch
katello-all-1.4.2-8.el6sat.noarch
katello-qpid-client-key-pair-1.0-1.noarch

How reproducible:
always

Steps to Reproduce:
1. Configure Sattelite6 with "free_ipa" LDAP server.
2. Create user role.
3. On CLI add LDAP group "admins" to created user role. "user_role add_ldap_group ...". You will see error here: "undefined method `empty?' for false:FalseClass".

Actual results:
error is shown while adding ldap group to user role.

Expected results:
it should add successfully if group exists, and will  show error message if group does not exist.

Additional info:
for "active_directory" LDAP it works fine.