Retire old "p2p" dev server

[pdehaan]

From The Etherpad:

"Lets retire https://p2p.dev.lcip.org in favor of https://fileshare.dev.mozaws.net"

I submitted a PR (#162) to change the dev server URL in the README.md file, but we should probably make sure we kill the https://p2p.dev.lcip.org/ server altogether so nobody uses it by mistake.

[pdehaan]

@dannycoates: Now that #166 (Rename stage/dev servers to "send.stage.mozaws.net") is done, do we need to retire the old fileshare.* domains as well?