Ubuntu distro install uses testrepository

The ubuntu tempest package still uses testrepository instead of stestr.

Change-Id: I69325f4d7e01940cf4099df0c56f1eaf9f060dd0

defaults/main.yml

@@ -16,6 +16,8 @@
 ## Verbosity Options
 debug: False
 
+stestr_executable: "{{ _stestr_executable | default('stestr') }}"
+
 # Install openstack tempest
 # set the tempest_install_method to source or distro
 # on choosing source it will install from git or venv

tasks/tempest_run.yml

@@ -44,7 +44,7 @@
       then
       . {{ tempest_venv_bin }}/activate
       fi
-      stestr last --subunit > {{ tempest_log_dir }}/testrepository.subunit
+      {{ stestr_executable }} last --subunit > {{ tempest_log_dir }}/testrepository.subunit
     args:
       chdir: "{{ tempest_workspace }}"
       executable: /bin/bash

vars/ubuntu.yml

@@ -16,6 +16,8 @@
 ## APT Cache options
 cache_timeout: 600
 
+_stestr_executable: "{{ (tempest_install_method == 'distro') | ternary('testr', 'stestr') }}"
+
 tempest_distro_packages:
   - git-core