make update_log() work if zone is not set

- update_log() is called to log update errors, but if those errors
  occur before the zone is set (for example, when returning NOTAUTH)
  it returns without logging anything.
26 jobs for update-log-fix in 8 minutes and 33 seconds (queued for 6 seconds)
Status Job ID Name Coverage
  Precheck
passed precheck:debian:sid:amd64 #61501
amd64 docker linux

00:00:20

 
  Build
passed build:centos:centos6:amd64 #61502
amd64 docker linux

00:02:11

passed build:centos:centos7:amd64 #61503
amd64 docker linux

00:02:46

passed build:clang:debian:stretch:amd64 #61504
amd64 docker linux

00:01:55

passed build:clang:debian:stretch:i386 #61508
i386 docker linux

00:01:29

passed build:debian:jessie:amd64 #61505
amd64 docker linux

00:01:24

passed build:debian:sid:amd64 #61507
amd64 docker linux

00:01:56

passed build:debian:sid:i386 #61509
i386 docker linux

00:01:31

passed build:debian:stretch:amd64 #61506
amd64 docker linux

00:01:56

passed pkcs11:build:debian:sid:amd64 #61510
amd64 docker linux

00:01:58

 
  Test
passed install:debian:sid:amd64 #61524
amd64 docker linux

00:02:21

passed pkcs11:systemtest:debian:sid:amd64 #61526
amd64 docker linux

00:05:22

passed pkcs11:unittest:debian:sid:amd64 #61525
amd64 docker linux

00:00:46

passed systemtest:centos:centos6:amd64 #61518
amd64 docker linux

00:04:42

passed systemtest:centos:centos7:amd64 #61519
amd64 docker linux

00:05:17

passed systemtest:debian:jessie:amd64 #61520
amd64 docker linux

00:05:23

passed systemtest:debian:sid:amd64 #61522
amd64 docker linux

00:05:16

passed systemtest:debian:sid:i386 #61523
i386 docker linux

00:04:54

passed systemtest:debian:stretch:amd64 #61521
linux amd64 docker

00:04:42

passed unittest:centos:centos6:amd64 #61511
amd64 docker linux

00:00:48

passed unittest:centos:centos7:amd64 #61512
amd64 docker linux

00:01:01

passed unittest:clang:debian:stretch:amd64 #61516
amd64 docker linux

00:00:43

passed unittest:debian:jessie:amd64 #61513
amd64 docker linux

00:00:54

passed unittest:debian:sid:amd64 #61515
amd64 docker linux

00:00:49

passed unittest:debian:sid:i386 #61517
i386 docker linux

00:00:46

passed unittest:debian:stretch:amd64 #61514
amd64 docker linux

00:00:46