fix ICMP packet checker

10 jobs for non-existent-ip in 1 minute and 27 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
passed #215840
amd64 linux docker
test:augeas

00:00:27

passed #215846
amd64 linux docker
test:comparative:kresd

00:01:23

passed #215841
amd64 linux docker
test:flake8

00:00:19

passed #215847
amd64 linux docker
test:latest:kresd

00:01:07

passed #215842
amd64 linux docker
test:mypy

00:00:27

passed #215843
amd64 linux docker
test:pylint

00:00:26

passed #215844
amd64 linux docker
test:rplint

00:00:20

passed #215849
amd64 linux docker
test:sanity:pdnsrecursor

00:00:29

passed #215848
amd64 linux docker
test:sanity:unbound

00:00:28

passed #215845
amd64 linux docker
test:unittests

00:00:21