OC4.0: Remove hardcoded admin_token

- admin_token set to an empty string in
contrail-webui-userauth.js as it is referred
to in code;
- removed reference to admin_token in
contrail-svc-monitor.conf

PROD-18320
PROD-20260

Change-Id: Id3c85a692cd1c5b4cada3887f91cb2604d62df9c
2 files changed