Let user to hide their OS type to be announced

When I join to relay to help netizens, I notice that my PC's OS type(ex. Linux, BSD, Win) and it's version are make to public.

In Apache, I can hide my PC's information by set "ServerToken Prod" flag. Why not Tor?

Please add something like: RelayAnnounceExtraInfo 0 (1 is default)

Trac:
Username: ikurua22