use COMMON_HTPASSWD_USER and COMMON_HTPASSWD_USER

use COMMON_HTPASSWD_USER and COMMON_HTPASSWD_USER
based on: 
XQUEUE_BASIC_AUTH_USER: "{{ COMMON_HTPASSWD_USER }}"
XQUEUE_BASIC_AUTH_PASSWORD: "{{ COMMON_HTPASSWD_PASS }}"
defined on roles/xqueue/defaults/main.yml