Drop privileges before running the git clone script

This causes the git repository files to be owned by the same user
as the one used by lsyncd to connect to the other repo servers.

Change-Id: I004e3bbef182b4dc6f18df5b9424190288f5e47d
Closes-Bug: #1620765
Depends-On: I3d974d578f3e2323415e36c40efa48036b517468

tasks/repo_clone_git.yml

@@ -22,6 +22,8 @@
 
 - name: Run clone process script
   shell: "bash /opt/op-clone-script.sh"
+  become: yes
+  become_user: "{{ repo_build_service_user_name }}"
   tags:
     - repo-clone-repos
 

tests/test-install-server.yml

@@ -25,12 +25,16 @@
         dest: "/var/www/repo/openstackgit/keystone"
         clone: yes
         update: yes
+      become: yes
+      become_user: "{{ repo_build_service_user_name }}"
     - name: Pre-cache the tempest git repository
       git:
         repo: "https://git.openstack.org/openstack/tempest"
         dest: "/var/www/repo/openstackgit/tempest"
         clone: yes
         update: yes
+      become: yes
+      become_user: "{{ repo_build_service_user_name }}"
     - name: Intentionally set the keystone repo remote origin to github
       shell: "git remote set-url origin https://github.com/openstack/keystone.git"
       args:

tests/test-vars.yml

@@ -17,6 +17,8 @@ openstack_release: testing
 repo_build_release_tag: "{{ openstack_release }}"
 galera_client_drop_config_file: false
 
+repo_build_service_user_name: "nginx"
+
 # Test data input for upper constraints validation
 repo_build_upper_constraints_overrides:
   - elasticsearch<2.1.0