odb: convert `odb_has_object()` flags into an enum
Following the reason in the preceding commit, convert the `odb_has_object()` flags into an enum. With this change, we would have catched the misuse of `odb_has_object()` that was fixed in a preceding commit as the compiler would have generated a warning: ../builtin/backfill.c:71:9: error: implicit conversion from enumeration type 'enum odb_object_info_flag' to different enumeration type 'enum odb_has_object_flag' [-Werror,-Wenum-conversion] 70 | if (!odb_has_object(ctx->repo->objects, &list->oid[i], | ~~~~~~~~~~~~~~ 71 | OBJECT_INFO_FOR_PREFETCH)) | ^~~~~~~~~~~~~~~~~~~~~~~~ 1 error generated. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>