Remove Buildbot version from host file

Buildbot master already obtains and publishes this in the UI.

contrib/ci-workers/templates/host.j2

@@ -1,4 +1,3 @@
 OS: {{ ansible_distribution }} {{ ansible_distribution_version }}
 Memory: {{ ansible_memtotal_mb }} MB
 CPU: {{ ansible_processor[1] }}
-{{ buildbot_worker_version.stdout }}

contrib/ci-workers/unix.yml

@@ -80,10 +80,6 @@
       with_items: "{{ python_modules }}"
       notify: restart buildbot-worker
 
-    - name: Get installed Buildbot version
-      command: buildbot-worker --version
-      register: buildbot_worker_version
-
     - name: Set up the Buildbot worker user
       user:
         name: "{{ buildbot_worker_user }}"