Use correct variable and change travis-test

Author: Sebastian Gumprich

.travis.yml

@@ -11,4 +11,4 @@ install:
 
 script:
   - ansible-playbook --syntax-check spec/travis.yml
-  - ansible-playbook --sudo -v --diff spec/travis.yml --skip-tags "sysctl"
+  - ansible-playbook --sudo -v --diff spec/travis.yml --skip-tags "sysctl" --extra-vars "os_security_users_allow=change_user"

roles/ansible-os-hardening/tasks/minimize_access.yml

@@ -15,4 +15,4 @@
 
 - name: change su-binary to only be accessible to user and group root
   file: dest='/bin/su' owner=root group=root mode=0750
-  when: security_users_allow|default(None) != None
+  when: os_security_users_allow != None