Removed useless "when"

With | default({}) in our with items, the task will be skipped if
the the variable is undefined. No need for a when.

Change-Id: Ie896084646a7393b92a8f9b3372510eb754dd35d

tasks/container_create.yml

@@ -212,7 +212,6 @@
         echo '{{ item.key }}={{ item.value }}' | tee -a /etc/environment
       fi
   with_dict: "{{ global_environment_variables | default({}) }}"
-  when: global_environment_variables is defined
   delegate_to: "{{ physical_host }}"
   tags:
     - lxc-container-proxy