"NFSv3 root=dhcp DHCP IP:path" fails on debian

[LaszloGombos]

https://github.com/dracutdevs/dracut/blob/master/test/TEST-20-NFS/test.sh#L152 times out in when running on a Debian container. 4 NFS subtests pass, but the 5th times out.

The same test passes on the Fedora-latest and Arch containers, so the concern seems to be distro dependent.

To reproduce, you need to apply PR https://github.com/dracutdevs/dracut/pull/1900