util/defer: Fix cancel() not being respected
util/defer: Fix cancel() not being respected

Message-Id: <0c863caea2d5f04fc65767a34ca1ec279380a33f@scylladb.com>

dreamsxin/seastar,kjniemi/seastar,syuu1228/seastar,scylladb/seastar,avikivity/seastar,syuu1228/seastar,cloudius-systems/seastar,scylladb/seastar,syuu1228/seastar,cloudius-systems/seastar,kjniemi/seastar,avikivity/seastar,dreamsxin/seastar,kjniemi/seastar,avikivity/seastar,cloudius-systems/seastar,dreamsxin/seastar,scylladb/seastar