Make devstack-gate stable jobs non-voting

Devstack-gate stable jobs used to be non-voting:
https://review.openstack.org/#/c/83076/

Currently they are voting:
https://review.openstack.org/#/c/155957/

This probably happend due to tempest using the same job names
and needing the jobs to vote. The devstack-gate jobs now have
-nv appended to the devstack-gate job names.

Change-Id: Id786d7ccc78a7d65cbed779331db15eb6b0bd46d

jenkins/jobs/projects.yaml

@@ -1770,16 +1770,27 @@
           branch-designator: '-juno'
           branch-override: stable/juno
       # Stable check jobs for testing devstack gate
+      # tempest also uses these job definitions
       - devstack-jobs:
           pipeline: check
           node: 'devstack-precise || devstack-trusty'
           branch-designator: '-icehouse'
           branch-override: stable/icehouse
+      - devstack-jobs:
+          pipeline: check
+          node: 'devstack-precise || devstack-trusty'
+          branch-designator: '-icehouse-nv'
+          branch-override: stable/icehouse
       - devstack-jobs:
           pipeline: check
           node: 'devstack-precise || devstack-trusty'
           branch-designator: '-juno'
           branch-override: stable/juno
+      - devstack-jobs:
+          pipeline: check
+          node: 'devstack-precise || devstack-trusty'
+          branch-designator: '-juno-nv'
+          branch-override: stable/juno
       # Periodic jobs for various branches
       - devstack-jobs:
           pipeline: periodic

zuul/layout.yaml

@@ -3200,13 +3200,13 @@ projects:
       - check-dg-hooks-dsvm
       - check-grenade-dsvm-partial-ncpu
       - check-swift-dsvm-functional
-      - check-tempest-dsvm-full-icehouse
-      - check-tempest-dsvm-neutron-icehouse
-      - check-tempest-dsvm-postgres-full-icehouse
-      - check-devstack-dsvm-cells-icehouse
-      - check-tempest-dsvm-full-juno
-      - check-tempest-dsvm-neutron-full-juno
-      - check-tempest-dsvm-postgres-full-juno
+      - check-tempest-dsvm-full-icehouse-nv
+      - check-tempest-dsvm-neutron-icehouse-nv
+      - check-tempest-dsvm-postgres-full-icehouse-nv
+      - check-devstack-dsvm-cells-icehouse-nv
+      - check-tempest-dsvm-full-juno-nv
+      - check-tempest-dsvm-neutron-full-juno-nv
+      - check-tempest-dsvm-postgres-full-juno-nv
       - check-tempest-dsvm-ironic-pxe_ssh
       - check-tempest-dsvm-f21
       - check-tempest-dsvm-centos7