neofetch: Priorize /etc/os-release
From os-release(5):
> The file /etc/os-release takes precedence over /usr/lib/os-release.
> Applications should check for the former, and exclusively use its
> data if it exists, and only fall back to /usr/lib/os-release if it
> is missing. Applications should not read data from both files at the
> same time.
Signed-off-by: Masanori Ogino <masanori.ogino@gmail.com>