format-patch: clear UNINTERESTING flag before prepare_bases
When users specify the commit range with 'Z..C' pattern for format-patch, all
the parents of Z (including Z) would be marked as UNINTERESTING which would
prevent revision walk in prepare_bases from getting the prerequisite commits,
thus `git format-patch --base <base_commit_sha> Z..C` won't be able to generate
the list of prerequisite patch ids. Clear UNINTERESTING flag with
clear_object_flags solves this issue.
Reported-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Xiaolong Ye <xiaolong.ye@intel.com>
Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>