Use the openshift S2I python image to build FPDC

Signed-off-by: Clement Verna <cverna@tutanota.com>

roles/openshift-apps/fpdc/templates/buildconfig.yml

@@ -18,6 +18,7 @@ spec:
     sourceStrategy:
       from:
         kind: ImageStreamTag
+        namespace: openshift
         name: python:3.6
   triggers:
 {% if fpdc_github_secret is defined %}