device: fix wrongly considering ipv6.may-fail for ipv4

Fixes: 5e71f016 ('device: merge stage3 and stage4 ip-config function for IPv4 and IPv6')
(cherry picked from commit a0179362)
21 jobs for nm-1-26 in 57 minutes and 49 seconds (queued for 14 seconds)
Status Job ID Name Coverage
  Test
passed #4466576
checkpatch

00:02:05

manual #4466584
allowed to fail manual
t_centos:7.5.1804
manual #4466585
allowed to fail manual
t_centos:7.6.1810
manual #4466586
allowed to fail manual
t_centos:7.7.1908
manual #4466587
allowed to fail manual
t_centos:7.8.2003
manual #4466588
allowed to fail manual
t_centos:8.1.1911
manual #4466594
allowed to fail manual
t_debian:10
manual #4466593
allowed to fail manual
t_debian:9
manual #4466596
allowed to fail manual
t_debian:sid
manual #4466595
allowed to fail manual
t_debian:testing
manual #4466577
allowed to fail manual
t_fedora:28
manual #4466578
allowed to fail manual
t_fedora:29
manual #4466579
allowed to fail manual
t_fedora:30
manual #4466580
allowed to fail manual
t_fedora:31
passed #4466581
t_fedora:32

00:57:47

manual #4466582
allowed to fail manual
t_fedora:33
manual #4466583
allowed to fail manual
t_fedora:rawhide
manual #4466589
allowed to fail manual
t_ubuntu:16.04
manual #4466590
allowed to fail manual
t_ubuntu:18.04
manual #4466592
allowed to fail manual
t_ubuntu:devel
manual #4466591
allowed to fail manual
t_ubuntu:rolling