Push pptr down into the FROM_MERGE branch of the if/else statement,
where it's actually used, and call commit_list_append() for appending
elements instead of playing tricks with commit_list_insert(). Call
copy_commit_list() in the amend branch instead of open-coding it. Don't
bother setting pptr in the final branch as it's not used thereafter.
Signed-off-by: Rene Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>