Clean up unnecessary pam entries as they are not needed. Add call to
puavo-pam-set-puavo-session-path to create user session directory.
Create the user specific session directory and set the user as the
owner. Needed on ltsp servers as the session is fetched from
Xsession.d scripts instead of PAM (PUAVO_SESSION_ID is known only
after ssh login so root access is not possible).