The default .bash_profile in /etc/skel sets $USERNAME to "".
It should either set it to $USER, or `id -un` (ala /etc/profile) or leave
it undefined. Setting it explicitly to empty makes no sense.
This problem also exists in 7.0
*** Bug 24257 has been marked as a duplicate of this bug. ***
This is now part of bash...
I have changed /etc/skel/.bash_profile to "unset USERNAME"
We should at some point investigate why /root/.bash_profile
sets USERNAME="root" or just through that away.
USERNAME isn't set at all in the current setup.