core: don't add prefix route for /32 addresses without peer

Kernel doesn't do it either, see function fib_add_ifaddr().
18 jobs for bg/prefix-route in 30 minutes and 32 seconds (queued for 2 seconds)
latest
Status Job ID Name Coverage
  Test
passed #800793
allowed to fail
checkpatch

00:01:27

manual #800799
allowed to fail manual
t_centos:7.5.1804
passed #800800
t_centos:7.6.1810

00:26:13

passed #800806
t_debian:10

00:20:12

passed #800805
t_debian:9

00:19:02

passed #800808
t_debian:sid

00:16:29

manual #800807
allowed to fail manual
t_debian:testing
manual #800794
allowed to fail manual
t_fedora:28
failed #800795
t_fedora:29

00:13:59

passed #800796
t_fedora:30

00:30:30

passed #800797
t_fedora:31

00:28:44

manual #800798
allowed to fail manual
t_fedora:rawhide
passed #800801
t_ubuntu:16.04

00:21:33

passed #800802
t_ubuntu:18.04

00:21:36

manual #800804
allowed to fail manual
t_ubuntu:devel
manual #800803
allowed to fail manual
t_ubuntu:rolling
 
  External
failed https://desktopqe-jenkins.rhev-ci-vms.eng.rdu2.redhat.com/job/beaker-NetworkManager-gitlab-trigger-code-upstream/840/

failed https://desktopqe-jenkins.rhev-ci-vms.eng.rdu2.redhat.com/job/beaker-NetworkManager-gitlab-trigger-code-upstream/840/

05:09:34

 
Name Stage Failure
failed
t_fedora:29 Test
+ xargs -0 grep -H '^'
+ true
+ echo '>>>> PRINT VALGRIND LOGS (valgrind test) (done)'
+ die 'valgrind test failed'
+ printf '%s\n' 'valgrind test failed'
+ exit 1
>>>> PRINT VALGRIND LOGS (valgrind test) (done)
valgrind test failed
ERROR: Job failed: exit code 1