DragonFly_RELEASE_2_4 branched

[Matthew Dillon]

    We've branched the repo, the DragonFly_RELEASE_2_4 branch now exists.
    It hasn't been tagged yet but it will soon.

    Please refrain from committing to master unless you also intend to
    MFC to the release branch.

    The ISO's will be built on Tuesday and we will officially release
    Wednesday after they have propagated to the mirrors.

                                                -Matt