Removendo o PPA removeu o erro:
sudo add-apt-repository --remove ppa:kernel-ppa/ppa
Erro completo:
Err:11 http://ppa.launchpad.net/kernel-ppa/ppa/ubuntu xenial Release
404 Not Found
Reading package lists... Done
E: The repository 'http://ppa.launchpad.net/kernel-ppa/ppa/ubuntu xenial Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
Normal sources.list :
$ cat /etc/apt/sources.list
deb http://ports.ubuntu.com/ xenial main restricted universe multiverse
deb-src http://ports.ubuntu.com/ xenial main restricted universe multiverse
deb http://ports.ubuntu.com/ xenial-updates main restricted universe multiverse
deb-src http://ports.ubuntu.com/ xenial-updates main restricted universe multiverse
deb http://ports.ubuntu.com/ xenial-security main restricted universe multiverse
deb-src http://ports.ubuntu.com/ xenial-security main restricted universe multiverse
deb http://ports.ubuntu.com/ xenial-backports main restricted universe multiverse
deb-src http://ports.ubuntu.com/ xenial-backports main restricted universe multiverse
Eu vejo que o kernel-ppa tem nenhuma pasta xenial dist . Como posso consertar este erro ou desativar o erro de lançar um erro sobre a falta de pasta xenial?