Retire remaining fuel repos (step 2)

Add noop-jobs for x/fuel repos including x/network-checker where
needed so that they can get retired.

Announcement:
http://lists.openstack.org/pipermail/openstack-discuss/2019-December/011675.html

Change-Id: Ic1ce7c1d357ce2c121035d0feafd0fe965a63e6c

zuul.d/projects.yaml

@@ -5394,7 +5394,7 @@
 - project:
     name: x/fuel-noop-fixtures
     templates:
-      - build-openstack-docs-pti
+      - noop-jobs
 
 - project:
     name: x/fuel-plugin-6wind-virtual-accelerator
@@ -6298,15 +6298,7 @@
 - project:
     name: x/network-checker
     templates:
-      - publish-to-pypi
-    check:
-      jobs:
-        - openstack-tox-pep8
-        - openstack-tox-py27
-    gate:
-      jobs:
-        - openstack-tox-pep8
-        - openstack-tox-py27
+      - noop-jobs
 
 - project:
     name: x/networking-6wind