Linux install - do not add "dropbox.list" to apt... (deb)

Linux install - do not add "dropbox.list" to apt... (deb install)  latest Linux versions use DEB822 Source Format now (.sources) or replace "dropbox.list" with "dropbox.surces"

example:

Types: deb
URIs: http://linux.dropbox.com/ubuntu/
Suites: questing
Components: main
Signed-By: /etc/apt/trusted.gpg.d/dropbox.asc