Fix outstanding cppcheck errors

lib/dns/sdb.c:1145:warning: Either the condition '(sdb)!=((void*)0)' is
redundant or there is possible null pointer dereference: sdb."

lib/dns/sdb.c:1208: Either the condition '(node)!=((void*)0)' is
redundant or there is possible null pointer dereference: sdbnode.
81 jobs for !3498 with each-cppcheck-v9_11 in 34 minutes and 32 seconds (queued for 21 seconds)
detached
Status Job ID Name Coverage
  Precheck
passed #867206
amd64 linux
autoreconf

00:00:25

passed #867208
amd64 linux
clang-format

00:00:21

passed #867209
amd64 linux
coccinelle

00:01:26

passed #867207
amd64 linux
misc

00:00:27

 
  Build
passed #867237
amd64 linux
clang:asan

00:06:12

passed #867245
amd64 linux
clang:buster:amd64

00:01:41

passed #867250
amd64 libvirt
clang:freebsd11.3:amd64

00:02:21

passed #867252
amd64 libvirt
clang:freebsd12.1:amd64

00:02:21

passed #867254
amd64 libvirt
clang:openbsd6.6:amd64

00:07:32

passed #867241
amd64 linux
clang:tsan

00:03:13

passed #867210
amd64 linux
gcc:alpine3.11:amd64

00:02:27

passed #867235
amd64 linux
gcc:asan

00:04:35

passed #867233
amd64 linux
gcc:bionic:amd64

00:02:41

passed #867217
amd64 linux
gcc:buster:amd64

00:02:23

passed #867211
amd64 linux
gcc:centos6:amd64

00:01:49

passed #867212
amd64 linux
gcc:centos7:amd64

00:02:15

passed #867213
amd64 linux
gcc:centos8:amd64

00:01:51

passed #867229
amd64 linux
gcc:fedora31:amd64

00:02:23

passed #867243
amd64 linux
gcc:mutexatomics

00:01:30

passed #867221
amd64 linux
gcc:out-of-tree

00:01:43

passed #867248
amd64 linux
gcc:pkcs11

00:01:46

passed #867219
amd64 linux
gcc:sid:amd64

00:03:16

passed #867223
arm64 linux
gcc:sid:arm64

00:03:26

passed #867225
i386 linux
gcc:sid:i386

00:02:21

passed #867215
amd64 linux
gcc:stretch:amd64

00:01:32

passed #867239
amd64 linux
gcc:tsan

00:02:46

passed #867227
amd64 linux
gcc:tumbleweed:amd64

00:02:21

passed #867231
amd64 linux
gcc:xenial:amd64

00:02:59

passed #867258
amd64 windows
msvc:windows:amd64

00:02:39

passed #867256
amd64 linux
nolibtool:sid:amd64

00:01:32

 
  Unit
passed #867288
amd64 linux
unit:clang:asan

00:01:40

passed #867296
amd64 linux
unit:clang:buster:amd64

00:00:31

passed #867300
amd64 libvirt
unit:clang:freebsd11.3:amd64

00:01:26

passed #867302
amd64 libvirt
unit:clang:freebsd12.1:amd64

00:00:50

failed #867292
amd64 linux allowed to fail
unit:clang:tsan

00:00:16

passed #867260
amd64 linux
unit:gcc:alpine3.11:amd64

00:00:44

passed #867286
amd64 linux
unit:gcc:asan

00:01:50

passed #867284
amd64 linux
unit:gcc:bionic:amd64

00:00:46

passed #867270
amd64 linux
unit:gcc:buster:amd64

00:00:39

passed #867262
amd64 linux
unit:gcc:centos6:amd64

00:00:39

passed #867264
amd64 linux
unit:gcc:centos7:amd64

00:00:46

passed #867266
amd64 linux
unit:gcc:centos8:amd64

00:00:37

passed #867280
amd64 linux
unit:gcc:fedora31:amd64

00:00:40

passed #867294
amd64 linux
unit:gcc:mutexatomics

00:00:44

passed #867298
amd64 linux
unit:gcc:pkcs11

00:00:43

passed #867272
amd64 linux
unit:gcc:sid:amd64

00:00:33

passed #867274
arm64 linux
unit:gcc:sid:arm64

00:00:56

passed #867276
i386 linux
unit:gcc:sid:i386

00:00:38

passed #867268
amd64 linux
unit:gcc:stretch:amd64

00:00:39

failed #867290
amd64 linux allowed to fail
unit:gcc:tsan

00:10:41

passed #867278
amd64 linux
unit:gcc:tumbleweed:amd64

00:00:48

passed #867282
amd64 linux
unit:gcc:xenial:amd64

00:00:51

passed #867304
amd64 linux
unit:nolibtool:sid:amd64

00:00:58

 
  System
passed #867335
amd64 linux
system:clang:asan

00:09:27

passed #867342
amd64 linux
system:clang:buster:amd64

00:07:21

passed #867346
amd64 libvirt
system:clang:freebsd11.3:amd64

00:08:32

passed #867348
amd64 libvirt
system:clang:freebsd12.1:amd64

00:08:42

failed #867339
amd64 linux allowed to fail
system:clang:tsan

00:03:51

passed #867307
amd64 linux
system:gcc:alpine3.11:amd64

00:07:49

passed #867333
amd64 linux
system:gcc:asan

00:09:50

passed #867331
amd64 linux
system:gcc:bionic:amd64

00:07:11

passed #867317
amd64 linux
system:gcc:buster:amd64

00:07:27

passed #867309
amd64 linux
system:gcc:centos6:amd64

00:07:52

passed #867311
amd64 linux
system:gcc:centos7:amd64

00:07:13

passed #867313
amd64 linux
system:gcc:centos8:amd64

00:07:21

passed #867327
amd64 linux
system:gcc:fedora31:amd64

00:07:16

passed #867341
amd64 linux
system:gcc:mutexatomics

00:07:16

passed #867344
amd64 linux
system:gcc:pkcs11

00:08:43

passed #867319
amd64 linux
system:gcc:sid:amd64

00:07:14

passed #867321
arm64 linux
system:gcc:sid:arm64

00:08:52

passed #867323
i386 linux
system:gcc:sid:i386

00:07:25

passed #867315
amd64 linux
system:gcc:stretch:amd64

00:07:10

failed #867337
amd64 linux allowed to fail
system:gcc:tsan

00:20:22

passed #867325
amd64 linux
system:gcc:tumbleweed:amd64

00:07:08

passed #867329
amd64 linux
system:gcc:xenial:amd64

00:06:47

passed #867350
amd64 linux
system:nolibtool:sid:amd64

00:07:32

 
  Docs
passed #867352
amd64 linux
docs

00:00:31

 
  Postcheck
passed #867360
amd64 linux
cppcheck

00:00:31

passed #867354
amd64 linux
flake8

00:01:41

passed #867356
amd64 linux
pylint

00:02:33

passed #867358
amd64 linux
scan-build

00:11:55

 
Name Stage Failure
failed
system:gcc:tsan System
No job log
failed
system:clang:tsan System
No job log
failed
unit:gcc:tsan Unit
No job log
failed
unit:clang:tsan Unit
No job log