Use fetch-subunit-output role

Currently there is a zuul-jobs role only used in this tempest job while
other jobs mostly use fetch-subunit-output role.

This changes tries to consolidate towards the most used role, to be able
to clean up zuul-jobs a bit.

Change-Id: I404760ba34767660f8816f48712e13dccad67440
Depends-On: https://review.openstack.org/548406

playbooks/post-tempest.yaml

@@ -1,7 +1,6 @@
 - hosts: all
   become: true
   roles:
-    - role: process-test-results
+    - role: fetch-subunit-output
-      test_results_dir: '{{ devstack_base_dir }}/tempest'
+      zuul_work_dir: '{{ devstack_base_dir }}/tempest'
-      tox_envdir: tempest
     - role: process-stackviz

roles/process-stackviz/README.rst

@@ -16,7 +16,7 @@ the stackviz archive embedded in test images.
    The stage directory where the input data can be found and
    the output will be produced.
 
-.. zuul:rolevar:: test_results_stage_name
+.. zuul:rolevar:: zuul_work_dir
-   :default: test_results
+   :default: {{ devstack_base_dir }}/tempest
 
-   The name of the subunit file to be used as input.
+   Directory to work in. It has to be a fully qualified path.

roles/process-stackviz/defaults/main.yaml

@@ -1,3 +1,3 @@
 devstack_base_dir: /opt/stack
 stage_dir: "{{ ansible_user_dir }}"
-test_results_stage_name: test_results
+zuul_work_dir: "{{ devstack_base_dir }}/tempest"

roles/process-stackviz/tasks/main.yaml

@@ -9,11 +9,11 @@
 
 - name: Check if subunit data exists
   stat:
-    path: "{{ stage_dir }}/{{ test_results_stage_name }}.subunit"
+    path: "{{ zuul_work_dir }}/testrepository.subunit"
   register: subunit_input
 
 - debug:
-    msg: "Subunit file could not be found at {{ stage_dir }}/{{ test_results_stage_name }}.subunit"
+    msg: "Subunit file could not be found at {{ zuul_work_dir }}/testrepository.subunit"
   when: not subunit_input.stat.exists
 
 - name: Install stackviz