git: .gitignore: Remove build products from list

[Matthew Dillon]

    Making them more visible to the repo solves a relatively minor build-time
    problem but it does it by trading against a potentially catastrophic
    commit to the repo.

    I would rather not have the potential for such a catastrophic commit to
    the repo, and solve the visibility issue for build-time checks some
    other way.  Having to fix massive repo bloat from a committer who makes
    a mistake and then potentially commits hundreds or thousands of files is
    a non-starter.  Minor commit errors by committers are not what I am
    worried here.  It's the big ones that those patterns help prevent.

						-Matt