tests: adjust collectd test for metric API change
tests: adjust collectd test for metric API change

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