retrive username when password expired

[Rich Graves]

Are you on 3.3.x? Release notes say that password is scrubbed but it's
username as well. If this is the issue then the quick fix is to add
this to conf/authn/password-authn-config.xml, and the medium fix is to
find username in some other context (it's probably still around
somewhere else).

<!-- Per 3.3 release notes needed for Duo's call to
usernamePasswordContext.getUsername() -->
<util:constant id="shibboleth.authn.Password.RemoveAfterValidation"
static-field="java.lang.Boolean.FALSE"/>