Improve certificates role testability

Move certs source path to defaults and make other small re-factoring.

Issue-ID: OOM-1694

Change-Id: Ie0a4b543b40314dc5a7772dd4667b1ad218d3543
Signed-off-by: Samuli Silvius <s.silvius@partner.samsung.com>
diff --git a/ansible/roles/application-install/tasks/install.yml b/ansible/roles/application-install/tasks/install.yml
index c0be12e..d2134d3 100644
--- a/ansible/roles/application-install/tasks/install.yml
+++ b/ansible/roles/application-install/tasks/install.yml
@@ -40,7 +40,7 @@
 
 - name: Register root certificate
   slurp:
-    src: '/certs/rootCA.crt'
+    src: "{{ playbook_dir }}/certs/rootCA.crt"
   register: root_cert
   delegate_to: localhost