Remote git subtree notice, it just confuse people

It seems this notice is just confusing people. That's not the first time I saw people telling me that they can't use subtree (like I did in the past - Ref #6).
It's totally not required now since a part of the script can create a branch if it doesn't exist.

Last time I got a similar comment was here https://github.com/gulpjs/gulp/pull/501#issuecomment-44803376