OSPF: Fix some trace messages

Missing argument in MTU change trace message can crash bird when MTU
change happens and trace messages are active.

Thanks to Alexander Velkov for the bugreport.
32 jobs from int-new in 6 minutes and 5 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Image
passed #186175
dind allowed to fail
docker_centos-6-amd64

00:00:19

passed #186176
dind allowed to fail
docker_centos-7-amd64

00:00:21

passed #186165
dind allowed to fail
docker_debian-7-amd64

00:00:20

passed #186169
dind allowed to fail
docker_debian-7-i386

00:00:19

passed #186166
dind allowed to fail
docker_debian-8-amd64

00:00:19

passed #186170
dind allowed to fail
docker_debian-8-i386

00:00:17

passed #186167
dind allowed to fail
docker_debian-9-amd64

00:00:19

passed #186171
dind allowed to fail
docker_debian-9-i386

00:00:17

passed #186168
dind allowed to fail
docker_debian-testing-amd64

00:00:20

passed #186172
dind allowed to fail
docker_debian-testing-i386

00:00:19

passed #186173
dind allowed to fail
docker_fedora-25-amd64

00:00:19

passed #186174
dind allowed to fail
docker_fedora-26-amd64

00:00:20

passed #186177
dind allowed to fail
docker_opensuse-42_3-amd64

00:00:21

passed #186178
dind allowed to fail
docker_ubuntu-14_04-amd64

00:00:21

passed #186179
dind allowed to fail
docker_ubuntu-16_04-amd64

00:00:19

 
  Build
passed #186186
docker linux amd64
build-centos-6-amd64

00:01:35

passed #186187
docker linux amd64
build-centos-7-amd64

00:01:35

passed #186180
docker linux amd64
build-debian-7-amd64

00:01:31

passed #186191
docker linux amd64
build-debian-7-i386

00:01:26

passed #186181
docker linux amd64
build-debian-8-amd64

00:01:34

passed #186192
docker linux amd64
build-debian-8-i386

00:01:21

passed #186182
docker linux amd64
build-debian-9-amd64

00:01:37

passed #186193
docker linux amd64
build-debian-9-i386

00:01:32

passed #186183
docker linux amd64
build-debian-testing-amd64

00:01:37

passed #186194
docker linux amd64
build-debian-testing-i386

00:01:35

passed #186184
docker linux amd64
build-fedora-25-amd64

00:01:32

passed #186185
docker linux amd64
build-fedora-26-amd64

00:01:31

passed #186195
freebsd amd64
build-freebsd-11-amd64

00:04:31

passed #186196
freebsd i386
build-freebsd-11-i386

00:04:55

passed #186188
docker linux amd64
build-opensuse-42_3-amd64

00:01:25

passed #186189
docker linux amd64
build-ubuntu-14_04-amd64

00:01:36

passed #186190
docker linux amd64
build-ubuntu-16_04-amd64

00:01:13