pkg/instance: fix gometalinter warnings
pkg/instance: fix gometalinter warnings

google/syzkaller,xairy/syzkaller,xairy/syzkaller,xairy/syzkaller,google/syzkaller,xairy/syzkaller,google/syzkaller,google/syzkaller,xairy/syzkaller,google/syzkaller,xairy/syzkaller,google/syzkaller,xairy/syzkaller,google/syzkaller