Partial revert of 131c5bf474dd25121832ad2e470525894c004227

* modules/openstack_project/files/zuul/layout.yaml:
131c5bf474dd25121832ad2e470525894c004227 added python jobs to
tripleo-image-elements which is not a python project. Remove those check
and gate jobs as they are not needed and currently prevent merges.

Change-Id: I99e78dedba1c3e68c82d41efc6ef5985a761d813