Wait more than 1 second for NSEC3 chain changes

One second may not be enough for an NSEC3 chain change triggered by an
UPDATE message to complete.  Wait up to 10 seconds when checking whether
a given NSEC3 chain change is complete in the "nsupdate" system test.

(cherry picked from commit f8746cdd)
40 jobs for !1848 with michal/minor-nsupdate-system-test-tweaks-v9_14 in 18 minutes and 33 seconds (queued for 5 seconds)
detached
Status Job ID Name Coverage
  Precheck
passed #219021
linux amd64
🐞:sid:amd64

00:00:44

passed #219020
linux amd64
misc:sid:amd64

00:00:19

 
  Build
passed #219032
linux amd64
asan:sid:amd64

00:02:53

passed #219033
linux amd64
clang:stretch:amd64

00:02:11

passed #219034
linux i386
clang:stretch:i386

00:01:39

passed #219022
linux amd64
docs:sid:amd64

00:00:43

passed #219031
linux amd64
gcc:bionic:amd64

00:02:17

passed #219023
linux amd64
gcc:centos6:amd64

00:01:48

passed #219024
linux amd64
gcc:centos7:amd64

00:02:37

passed #219029
linux amd64
gcc:fedora29:amd64

00:02:54

passed #219025
linux amd64
gcc:jessie:amd64

00:01:23

passed #219027
linux amd64
gcc:sid:amd64

00:01:44

passed #219028
linux i386
gcc:sid:i386

00:03:11

passed #219026
linux amd64
gcc:stretch:amd64

00:01:40

passed #219030
linux amd64
gcc:xenial:amd64

00:01:34

passed #219035
linux amd64
pkcs11:sid:amd64

00:01:04

 
  Test
passed #219054
linux amd64
system:asan:sid:amd64

00:08:29

passed #219141
linux amd64
system:gcc:bionic:amd64

00:06:43

passed #219036
linux amd64
system:gcc:centos6:amd64

00:07:47

passed #219038
linux amd64
system:gcc:centos7:amd64

00:07:48

passed #219048
linux amd64
system:gcc:fedora29:amd64

00:06:58

passed #219040
linux amd64
system:gcc:jessie:amd64

00:07:46

passed #219044
linux amd64
system:gcc:sid:amd64

00:06:46

passed #219046
linux i386
system:gcc:sid:i386

00:07:22

passed #219042
linux amd64
system:gcc:stretch:amd64

00:07:22

passed #219050
linux amd64
system:gcc:xenial:amd64

00:07:24

passed #219057
linux amd64
system:pkcs11:sid:amd64

00:07:59

passed #219055
linux amd64
unit:asan:sid:amd64

00:01:04

passed #219056
linux amd64
unit:clang:stretch:amd64

00:00:50

passed #219053
linux amd64
unit:gcc:bionic:amd64

00:00:47

passed #219037
linux amd64
unit:gcc:centos6:amd64

00:00:51

passed #219039
linux amd64
unit:gcc:centos7:amd64

00:00:51

passed #219049
linux amd64
unit:gcc:fedora29:amd64

00:00:45

passed #219041
linux amd64
unit:gcc:jessie:amd64

00:00:28

passed #219045
linux amd64
unit:gcc:sid:amd64

00:00:53

passed #219047
linux i386
unit:gcc:sid:i386

00:00:48

passed #219043
linux amd64
unit:gcc:stretch:amd64

00:00:52

passed #219051
linux amd64
unit:gcc:xenial:amd64

00:00:52

passed #219058
linux amd64
unit:pkcs11:sid:amd64

00:00:51

failed #219052
linux amd64
system:gcc:bionic:amd64

00:07:48