modules/hints: plug a memory leak in .use_nodata()

It was tiny, but still.
31 jobs for <span class="ref-name">hints-use_nodata-leak</span> in 40 minutes and 29 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
passed #218078
docker linux amd64
build:asan:linux:amd64

00:01:17

passed #218077
docker linux amd64
build:linux:amd64

00:01:05

passed #218079
docker linux amd64 allowed to fail
srpm

00:00:25

 
  Test
passed #218088
docker linux amd64
deckard:linux:amd64

00:01:46

passed #218096
privileged
distro:epel-7

00:02:04

passed #218095
privileged
distro:fedora-29

00:02:43

passed #218087
docker
doc

00:00:47

passed #218085
dind
docker:build

00:02:09

passed #218086
docker linux amd64
installcheck:linux:amd64

00:00:42

passed #218089
docker linux amd64
installcheck:valgrind:linux:amd64

00:02:01

passed #218082
docker
lint:c

00:02:40

passed #218083
docker
lint:clang-scan-build

00:01:03

passed #218081
docker
lint:lua

00:00:29

passed #218080
docker linux amd64
lint:pedantic

00:01:27

passed #218090
docker
osx:build

00:02:23

passed #218092
docker linux amd64
pytests:lint

00:00:44

passed #218093
docker linux amd64
pytests:run

00:01:58

passed #218094
docker linux amd64
respdiff:iter:udp:linux:amd64

00:02:15

passed #218084
docker linux amd64
test:linux:amd64

00:00:58

passed #218091
docker linux amd64
test:linux:amd64:valgrind

00:01:20

 
  Extended
passed #218097
docker linux amd64
pytests:extended

00:03:26

passed #218098
respdiff
respdiff:fwd-tls6-kresd.udp6

00:12:51

passed #218099
respdiff
respdiff:fwd-udp6-kresd.udp6

00:18:53

failed #218103
respdiff
respdiff:fwd-udp6-unbound.tcp6

00:26:23

failed #218104
respdiff
respdiff:fwd-udp6-unbound.tls6

00:36:24

failed #218102
respdiff
respdiff:fwd-udp6-unbound.udp6

00:27:23

passed #218101
respdiff
respdiff:iter.tls6

00:33:24

passed #218100
respdiff
respdiff:iter.udp6

00:21:23

failed #218105
respdiff
resperf:fwd-tls6.udp-asan

00:28:19

failed #218106
respdiff
resperf:fwd-udp6.udp-asan

00:24:19

passed #218107
respdiff
resperf:iter.udp-asan

00:26:49

 
Name Stage Failure
failed
respdiff:fwd-udp6-unbound.udp6 Extended
Running after script...
$ cp -t . respdiff_commitdir/$RESPDIFF_TEST/j* ||:
$ cp -t . respdiff_commitdir/*$RESPDIFF_TEST*.png ||:
Uploading artifacts...
Runtime platform arch=amd64 os=linux pid=46810 revision=f100a208 version=11.6.0
./j*: found 14 matching files
./*.png: found 3 matching files
Uploading artifacts to coordinator... ok id=218102 responseStatus=201 Created token=5Rn9xoHx
ERROR: Job failed: exit status 1
failed
respdiff:fwd-udp6-unbound.tls6 Extended
Running after script...
$ cp -t . respdiff_commitdir/$RESPDIFF_TEST/j* ||:
$ cp -t . respdiff_commitdir/*$RESPDIFF_TEST*.png ||:
Uploading artifacts...
Runtime platform arch=amd64 os=linux pid=47302 revision=f100a208 version=11.6.0
./j*: found 14 matching files
./*.png: found 3 matching files
Uploading artifacts to coordinator... ok id=218104 responseStatus=201 Created token=94zyqsNp
ERROR: Job failed: exit status 1
failed
resperf:fwd-udp6.udp-asan Extended
kresd_fwd_target_1  | SUMMARY: AddressSanitizer: 65600 byte(s) leaked in 4 allocation(s).
$ exit $EXITCODE
Running after script...
$ cp -t . resperf_commitdir/$RESPERF_TEST/j* ||:
Uploading artifacts...
Runtime platform arch=amd64 os=linux pid=46493 revision=f100a208 version=11.6.0
./j*: found 7 matching files
Uploading artifacts to coordinator... ok id=218106 responseStatus=201 Created token=KzFDecz7
ERROR: Job failed: exit status 1
failed
respdiff:fwd-udp6-unbound.tcp6 Extended
Running after script...
$ cp -t . respdiff_commitdir/$RESPDIFF_TEST/j* ||:
$ cp -t . respdiff_commitdir/*$RESPDIFF_TEST*.png ||:
Uploading artifacts...
Runtime platform arch=amd64 os=linux pid=46665 revision=f100a208 version=11.6.0
./j*: found 14 matching files
./*.png: found 3 matching files
Uploading artifacts to coordinator... ok id=218103 responseStatus=201 Created token=iEJ6maky
ERROR: Job failed: exit status 1
failed
resperf:fwd-tls6.udp-asan Extended
Attaching to dir_8910_kresd_fwd_target_1, dir_8910_kresd_1
$ exit $EXITCODE
Running after script...
$ cp -t . resperf_commitdir/$RESPERF_TEST/j* ||:
Uploading artifacts...
Runtime platform arch=amd64 os=linux pid=46885 revision=f100a208 version=11.6.0
./j*: found 7 matching files
Uploading artifacts to coordinator... ok id=218105 responseStatus=201 Created token=ioRkjX96
ERROR: Job failed: exit status 1