Fix install-plugins role

install-plugins role didn't take into account upper
constraints when installing plugins, this review
fixes that.

Change-Id: I82d81aad7952ce9d03c42187e4ae957043f59397

.zuul.yaml

@@ -52,6 +52,7 @@
       - openstack/devstack
       - openstack/designate
       - openstack/designate-tempest-plugin
+      - openstack/requirements
     roles:
       - zuul: openstack/python-tempestconf
       - zuul: openstack/tempest

roles/install-plugins/tasks/main.yaml

@@ -6,7 +6,11 @@
 
 - name: Install plugins
   become: yes
-  command: tox -evenv-tempest -- pip install {{ item }}
+  command:
+    cmd: >
+      tox -evenv-tempest --
+      pip install {{ item }}
+      --constraint {{ ansible_user_dir }}/{{ zuul.projects['opendev.org/openstack/requirements'].src_dir }}/upper-constraints.txt
   with_items: "{{ plugins_paths }}"
   args:
     chdir: "{{devstack_base_dir}}/tempest"