Bug in git citool when staging symlink as replacement for submodule

[Adam Spiers <git@adamspiers.org>]

I found some strange behaviour in git citool when trying to stage a
symlink into the index as a replacement for a (non-registered) submodule.
I just reproduced with latest master (1.7.11.rc0.55.gb2478aa):

    mkdir repo
    cd repo
    git init
    echo foo > one
    git add one
    git commit -m'first commit'

    mkdir two
    cd two
    git init
    echo foo > submodule-file
    git add submodule-file
    git commit -m'first submodule commit'

    cd ..

    git add two
    git commit -m'second commit'

    rm -rf two
    ln -s one two

    git citool

At this point, git citool outputs:

    error: Unhandled submodule diff marker: {@@ }
    error: Unhandled submodule diff marker: {+on}

Now if I press Control-T to try to stage 'two' into the index, I get a new
dialog which says:

    Updating the Git index failed. A rescan will be automatically
    started to resynchronize git-gui.

    error: two is already a gitlink, not replacing
    fatal: Unable to process path two


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I can work around via 'git add two', but it would be nice if citool
handled this correctly.

Thanks!
Adam