Tooz 6.0.1 includes commit [1], which introduced
parsing the username from the Redis connection URL.
As a result, services started authenticating as admin
which, by the way, was incorrect even before, as either
a created user or the default one should have been used.

The reason it worked before is simply because the username
'admin' wasn't parsed anywhere.

This patch fixes the user being used and sets the correct
'default' one.

[1] https://review.opendev.org/c/openstack/tooz/+/907656

Closes-Bug: #2056667
Depends-On: https://review.opendev.org/c/openstack/kolla/+/911703
Change-Id: I5568dba15fa98e009ad4a9e41756aba0fa659371