A recent patch series renamed the get_commit_tree_from_graph method but
forgot to update the coccinelle script that exempted it from rules
regarding accesses to 'maybe_tree'. This fixes that oversight to bring
the coccinelle scripts back to a good state.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>