[notice] the tip of 'next' rewound

As announced earlier, 'next' was rebuild directly on top of 'master',
dropping a few topics that has been reverted during 1.6.6 period and
currently has only the following topics:

    nd/sparse: sparse checkout;
    tr/http-updates: support for non-Basic auth methods to http transport;
    jc/checkout-merge-base: "git checkout foo...bar" (notice three-dot);
    jh/notes: an early part of "git notes" update;
    jk/maint-1.6.5-reset-hard: fix "GIT_WORK_TREE=somewhere git reset --hard";