setup post job for sahara-extra

this changes setups additional post job for sahara-extra artifacts.
we already have the script that make all needed build operations, and
it lives in sahara-extra repository.

since some these artifacts should be stored per branch, we are passing
branch as argument of the script so that after successful build all
needed stuff will be in to appropriate place ('dist/newton/' directory
for example).

Change-Id: I2d2a29f71ba11da46c9a313132af39709cc1ef61

jenkins/jobs/sahara.yaml

@@ -84,7 +84,9 @@
       - link-logs
       - shell: |
           #!/bin/bash -xe
-          tools/build-all-artifacts.sh
+          export BRANCH=${{ZUUL_BRANCH:-master}}
+          # tell to script where it should place dist results
+          tools/build-all-artifacts.sh $BRANCH
 
 
 - publisher:
@@ -101,7 +103,27 @@
 
 - job:
     name: 'gate-sahara-extra-artifacts'
-    node: ubuntu-trusty
+    node: ubuntu-xenial
+
+    wrappers:
+      - build-timeout:
+          timeout: 65
+      - timestamps
+
+    builders:
+      - link-logs
+      - net-info
+      - gerrit-git-prep
+      - install-distro-packages
+      - sahara-extra-build
+
+    publishers:
+      - console-log
+
+
+- job:
+    name: 'post-sahara-extra-artifacts'
+    node: ubuntu-xenial
 
     wrappers:
       - build-timeout:

zuul/layout.yaml

@@ -2471,8 +2471,8 @@ jobs:
   - name: gate-grenade-dsvm-sahara
     voting: false
 
-  - name: ^gate-sahara-extra-artifacts$
-    voting: false
+  - name: ^(gate|post)-sahara-extra-artifacts$
+    branch: ^(?!stable/(mitaka|liberty|icehouse)).*$
 
   - name: ^sahara-coverage-db-ubuntu-(trusty|xenial)
     voting: false
@@ -15002,8 +15002,10 @@ projects:
     gate:
       - gate-sahara-extra-pep8-ubuntu-trusty
       - gate-sahara-extra-pep8-ubuntu-xenial
+      - gate-sahara-extra-artifacts
     post:
       - sahara-extra-branch-tarball
+      - post-sahara-extra-artifacts
 
 # TODO: add docs
   - name: openstack/sahara-image-elements