sequencer: fix a memory leak in sequencer_continue()

sequencer: fix a memory leak in sequencer_continue()

When continuing an interactive rebase after a merge conflict was solved,
if the resolution could not be committed, sequencer_continue() would
return early without releasing its todo list, resulting in a memory
leak.  This plugs this leak by jumping to the end of the function, where
the todo list is deallocated.

Signed-off-by: Alban Gruin <alban.gruin@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>