Make sure that functional test triggered on sample changes

To be able to define different irrelevant-files for the functional jobs
than the ones defined in openstack-zuul-jobs we need to copy the jobs to
the nova tree and modify the fields in tree.

Technically we could factor out the irrelevant-files regexp list from
functional and functional-py35 jobs as they are the same today. However
in the future when they diverge we cannot simply override the
irrelevant-files in one of the jobs. Therefore this patch does not
introduce a common base job for functinal and functional-py35 jobs
to discurage trying to override.

The openstack-tox-functional and fuctional-py35 are removed from the
nova part of the project-config in
I56d44f8dff41dbf3b2ff2382fa39b364f55f9a44

NOTE(mriedem): The nova-tox-functional-py35 job is not backported to
Ocata because the job didn't work until Pike.

Depends-On: https://review.openstack.org/538619/

Closes-Bug: #1742962
Change-Id: Ia684786d1622da7af31aa4479fc883a7c65848ff
(cherry picked from commit d4377c2d53)
(cherry picked from commit efa832f35d)

.zuul.yaml

@@ -0,0 +1,25 @@
+- job:
+    name: nova-tox-functional
+    parent: openstack-tox
+    description: |
+      Run tox-based functional tests for the OpenStack Nova project with Nova
+      specific irrelevant-files list. Uses tox with the ``functional``
+      environment.
+    irrelevant-files:
+      - ^.*\.rst$
+      - ^api-.*$
+      - ^doc/source/.*$
+      - ^nova/locale/.*$
+      - ^placement-api-ref/.*$
+      - ^releasenotes/.*$
+    vars:
+      tox_envlist: functional
+
+- project:
+    name: openstack/nova
+    check:
+      jobs:
+        - nova-tox-functional
+    gate:
+      jobs:
+        - nova-tox-functional