After upgrading to 4.0 user avatar can be lost

When having FeCru with < 4.0 configured with remote user directory (Crowd/Jira) with forced lowercase username and then upgrading to FeCru 4.0 users with mixed case user names will loose their avatars.

In details:

Let's take “John" example.

Pre 4.0

We have Crowd directory with forced lower case turned on and a user with “John” username.
In cru_user we have “john” user and his avatar is saved under hash(“john”).

In 4.0

“john” is still present in cru_user with the user name lowercased, in cwd_user we keep both username “John” / lowercase userame “john”

The avatar is expected to be found in hash(fecruUser.getUsername) where the username is taken from cwd_user so it is hash(“John”) and can’t be found.