ipaclient/tasks/main.yml: Fix undefined ipaclient_packages error with include_role

The relative import of the distribution specific vars files requires to use
is not working. {{ role_path }} needs to be used to force the load of the
proper files.

roles/ipaclient/tasks/main.yml

@@ -4,10 +4,10 @@
 - name: Import variables specific to distribution
   include_vars: "{{ item }}"
   with_first_found:
-    - "vars/{{ ansible_distribution }}-{{ ansible_distribution_version }}.yml"
-    - "vars/{{ ansible_distribution }}-{{ ansible_distribution_major_version }}.yml"
-    - "vars/{{ ansible_distribution }}.yml"
-    - "vars/default.yml"
+    - "{{ role_path }}/vars/{{ ansible_distribution }}-{{ ansible_distribution_version }}.yml"
+    - "{{ role_path }}/vars/{{ ansible_distribution }}-{{ ansible_distribution_major_version }}.yml"
+    - "{{ role_path }}/vars/{{ ansible_distribution }}.yml"
+    - "{{ role_path }}/vars/default.yml"
 
 - name: Install IPA client
   include: tasks/install.yml