Fix control flow issue CID 314969 in zoneconf.c

Coverity Scan identified the following issue in bin/named/zoneconf.c:

    *** CID 314969:  Control flow issues  (DEADCODE)
    /bin/named/zoneconf.c: 2212 in named_zone_inlinesigning()

    if (!inline_signing && !zone_is_dynamic &&
        cfg_map_get(zoptions, "dnssec-policy", &signing) == ISC_R_SUCCESS &&
        signing != NULL)
    {
        if (strcmp(cfg_obj_asstring(signing), "none") != 0) {
            inline_signing = true;
    >>>     CID 314969:  Control flow issues  (DEADCODE)
    >>>     Execution cannot reach the expression ""no"" inside this statement: "dns_zone_log(zone, 1, "inli...".
            dns_zone_log(
                zone, ISC_LOG_DEBUG(1), "inline-signing: %s",
                inline_signing
                ? "implicitly through dnssec-policy"
                : "no");
        } else {
                ...
        }
    }

This is because we first set 'inline_signing = true' and then check
its value in 'dns_zone_log'.
79 jobs for !4573 with 2364-cid314969-coverity-deadcode-zoneconf in 39 minutes and 55 seconds (queued for 7 seconds)
detached
Status Job ID Name Coverage
  Autoconf
passed #1411044
linux amd64
autoreconf

00:00:18

 
  Precheck
passed #1411046
linux amd64
clang-format

00:00:17

passed #1411047
linux amd64
coccinelle

00:03:46

passed #1411048
linux amd64
danger

00:00:13

passed #1411045
linux amd64
misc

00:00:17

passed #1411049
linux amd64
tarball-create

00:01:27

 
  Build
passed #1411062
linux amd64
clang:asan

00:02:14

passed #1411066
linux amd64
clang:buster:amd64

00:01:00

passed #1411069
amd64 libvirt
clang:freebsd11:amd64

00:01:13

passed #1411070
amd64 libvirt
clang:freebsd12:amd64

00:01:06

passed #1411071
amd64 libvirt
clang:openbsd:amd64

00:02:16

passed #1411064
linux amd64
clang:tsan

00:01:03

passed #1411050
linux amd64
gcc:alpine3.12:amd64

00:00:52

passed #1411061
linux amd64
gcc:asan

00:01:46

passed #1411054
linux amd64
gcc:buster:amd64

00:00:46

passed #1411051
linux amd64
gcc:centos7:amd64

00:00:49

passed #1411052
linux amd64
gcc:centos8:amd64

00:00:48

passed #1411060
linux amd64
gcc:focal:amd64

00:00:50

passed #1411065
linux amd64
gcc:mutexatomics

00:00:48

passed #1411056
linux amd64
gcc:out-of-tree

00:00:58

passed #1411055
linux amd64
gcc:sid:amd64

00:01:07

passed #1411057
linux i386
gcc:sid:i386

00:00:51

passed #1411067
linux amd64
gcc:softhsm2.4

00:00:49

passed #1411068
linux amd64
gcc:softhsm2.6

00:00:54

passed #1411053
linux amd64
gcc:stretch:amd64

00:00:56

passed #1411063
linux amd64
gcc:tsan

00:01:14

passed #1411058
linux amd64
gcc:tumbleweed:amd64

00:00:53

passed #1411059
linux amd64
gcc:xenial:amd64

00:00:51

passed #1411072
amd64 windows
msvc:windows:amd64

00:00:44

 
  Unit
passed #1411084
linux amd64
unit:clang:asan

00:01:31

passed #1411088
linux amd64
unit:clang:buster:amd64

00:01:05

passed #1411091
amd64 libvirt
unit:clang:freebsd11:amd64

00:01:33

passed #1411092
amd64 libvirt
unit:clang:freebsd12:amd64

00:01:28

passed #1411093
amd64 libvirt
unit:clang:openbsd:amd64

00:02:59

passed #1411086
linux amd64
unit:clang:tsan

00:03:07

passed #1411073
linux amd64
unit:gcc:alpine3.12:amd64

00:01:05

passed #1411120
linux amd64
unit:gcc:asan

00:01:16

passed #1411077
linux amd64
unit:gcc:buster:amd64

00:02:03

passed #1411074
linux amd64
unit:gcc:centos7:amd64

00:01:13

passed #1411075
linux amd64
unit:gcc:centos8:amd64

00:01:07

passed #1411082
linux amd64
unit:gcc:focal:amd64

00:01:06

passed #1411087
linux amd64
unit:gcc:mutexatomics

00:01:04

passed #1411078
linux amd64
unit:gcc:sid:amd64

00:01:07

passed #1411079
linux i386
unit:gcc:sid:i386

00:01:07

passed #1411089
linux amd64
unit:gcc:softhsm2.4

00:01:06

passed #1411090
linux amd64
unit:gcc:softhsm2.6

00:01:07

passed #1411076
linux amd64
unit:gcc:stretch:amd64

00:01:10

passed #1411085
linux amd64
unit:gcc:tsan

00:04:12

passed #1411080
linux amd64
unit:gcc:tumbleweed:amd64

00:01:05

passed #1411081
linux amd64
unit:gcc:xenial:amd64

00:01:11

failed #1411083
linux amd64
unit:gcc:asan

00:01:26

 
  System
passed #1411105
linux amd64
system:clang:asan

00:13:17

passed #1411109
linux amd64
system:clang:buster:amd64

00:12:07

passed #1411112
amd64 libvirt
system:clang:freebsd11:amd64

00:11:59

passed #1411374
amd64 libvirt
system:clang:freebsd12:amd64

00:11:45

passed #1411107
linux amd64
system:clang:tsan

00:15:02

passed #1411094
linux amd64
system:gcc:alpine3.12:amd64

00:12:37

passed #1411104
linux amd64
system:gcc:asan

00:13:33

passed #1411098
linux amd64
system:gcc:buster:amd64

00:13:27

passed #1411095
linux amd64
system:gcc:centos7:amd64

00:12:32

passed #1411096
linux amd64
system:gcc:centos8:amd64

00:12:10

passed #1411103
linux amd64
system:gcc:focal:amd64

00:12:24

passed #1411108
linux amd64
system:gcc:mutexatomics

00:12:25

passed #1411099
linux amd64
system:gcc:sid:amd64

00:11:54

passed #1411100
linux i386
system:gcc:sid:i386

00:12:31

passed #1411110
linux amd64
system:gcc:softhsm2.4

00:12:01

passed #1411111
linux amd64
system:gcc:softhsm2.6

00:11:56

passed #1411097
linux amd64
system:gcc:stretch:amd64

00:11:27

passed #1411106
linux amd64
system:gcc:tsan

00:15:29

passed #1411373
linux amd64
system:gcc:tumbleweed:amd64

00:12:33

passed #1411102
linux amd64
system:gcc:xenial:amd64

00:11:29

failed #1411113
amd64 libvirt
system:clang:freebsd12:amd64

00:12:11

failed #1411101
linux amd64
system:gcc:tumbleweed:amd64

00:12:10

 
  Docs
passed #1411114
linux amd64
docs

00:00:41

 
  Postcheck
passed #1411118
linux amd64
cppcheck

00:00:41

passed #1411115
linux amd64
flake8

00:00:19

passed #1411119
linux amd64
gcov

00:00:32

77.0%
passed #1411116
linux amd64
pylint

00:00:22

passed #1411117
linux amd64
scan-build

00:03:52