The backend_url option can sometimes contain secrets.
For example when redis coordination backend is used and authentication
is enabled in redis, the plain redis password is put as an URL element.
[coordination]
backend_url=redis://:password@127.0.0.1:6379
Closes-Bug: #2012246
Change-Id: Ib918532d82c4633add7fad9c8441868cfd84001b