tests: print contents of group_vars/all after modification

This is just nice to see in the test output so we know exactly what
configuration is going to be used.

Signed-off-by: Andrew Schoen <aschoen@redhat.com>
(cherry picked from commit 0e6d89b9db)

tests/functional/rhcs_setup.yml

@@ -46,6 +46,9 @@
         dest: "{{ change_dir }}/group_vars/all"
       when: change_dir is defined
 
+    - name: print contents of {{ change_dir }}/group_vars/all
+      command: "cat {{ change_dir }}/group_vars/all"
+
 - hosts: all
   gather_facts: true
   become: yes