Merge pull request #2131 from edx/feanil/fix_sandbox_xqueue

Don't use ELB pre/post logic with single instance installations.

playbooks/roles/edx_ansible/templates/update.j2

@@ -46,7 +46,7 @@ declare -A repos_to_cmd
 edx_ansible_cmd="{{ edx_ansible_venv_bin }}/ansible-playbook -i localhost, -c local $extra_args"
 
 repos_to_cmd["edx-platform"]="$edx_ansible_cmd edxapp.yml -e 'edx_platform_version=$2'"
-repos_to_cmd["xqueue"]="$edx_ansible_cmd xqueue.yml -e 'xqueue_version=$2'"
+repos_to_cmd["xqueue"]="$edx_ansible_cmd xqueue.yml -e 'xqueue_version=$2' -e 'elb_pre_post=false'"
 repos_to_cmd["cs_comments_service"]="$edx_ansible_cmd forum.yml -e 'forum_version=$2'"
 repos_to_cmd["xserver"]="$edx_ansible_cmd xserver.yml -e 'xserver_version=$2'"
 repos_to_cmd["configuration"]="$edx_ansible_cmd edx_ansible.yml -e 'configuration_version=$2'"