[patch] git: cleanup in ls-tree.c

[patch] git: cleanup in ls-tree.c

cleanup: this patch adds a free() to ls-tree.c.

(Technically it's not a memory leak yet because the buffer is allocated
once by the function and then the utility exits - but it's a tad cleaner
to not leave such assumptions in the code, so that if someone reuses the
function (or extends the utility to include a loop) the uncleanliness
doesnt develop into a real memory leak.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Forward-ported.

Signed-off-by: Petr Baudis <pasky@ucw.cz>