merge-ort: fix type of local 'clean' var in handle_content_merge ()

handle_content_merge() returns an int. Every caller of handle_content_merge() expects an int. However, we declare a local variable 'clean' that we use for the return value to be unsigned. To make matters worse, we also assign 'clean' the return value of merge_submodule() in one codepath, which is defined to return an int. It seems that the only reason to have 'clean' be unsigned was to allow a cutesy bit manipulation operation to be well-defined. Fix the type of the 'clean' local in handle_content_merge(). Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>