Fix wrong pathname in pre install task

/etc/cinder was used instead of /etc/ceilometer in the task
that removes config directory. So the config directory was
never removed.

Change-Id: Idb8555a98e412cde15a5a328a4a7471202aaf6c3

tasks/ceilometer_pre_install.yml

@@ -54,7 +54,7 @@
 
     - name: Remove the config directory
       file:
-        path: "/etc/cinder"
+        path: "/etc/ceilometer"
         state: absent
       when:
         - ceilometer_conf_dir_stat.stat.isdir is defined and