Pin dogpile.cache<1.4.0

With dogpile.cache-1.4.0 browbeat scenario runs fails
as described in the below bug, work around it by pinning
to working version.

Closes-Bug: #2110045
Change-Id: I568d664971296bf1065e78125b378ffd7a69d654

ansible/install/roles/rally/tasks/main.yml

@@ -67,6 +67,13 @@
     name: 'python-novaclient<18.3.0'
     virtualenv: "{{ rally_venv }}"
 
+# Till browbeat code is compatible with dogpile.cache-1.4.0
+# https://bugs.launchpad.net/openstack-browbeat/+bug/2110045
+- name: Ensure dogpile.cache<1.4.0
+  pip:
+    name: 'dogpile.cache<1.4.0'
+    virtualenv: "{{ rally_venv }}"
+
 - name: Create rally configuration directory
   file:
     path: "{{ rally_venv }}/etc/rally"