reset taskmgr mode immediately after returning from zone load

all privileged tasks are complete by the time we return from
isc_task_endexclusive(), so it makes sense to reset the taskmgr
mode to non-privileged right then.
70 jobs for !5010 with each-taskmgr-setmode in 5 minutes and 6 seconds (queued for 20 seconds)
latest detached
Status Job ID Name Coverage
  Autoconf
passed #1705976
amd64 linux
autoreconf

00:00:16

 
  Precheck
passed #1705978
amd64 linux
clang-format

00:00:19

passed #1705979
amd64 linux
coccinelle

00:03:48

passed #1705980
amd64 linux
danger

00:00:18

passed #1705977
amd64 linux
misc

00:00:19

passed #1705981
amd64 linux
tarball-create

00:01:26

 
  Build
passed #1705992
amd64 linux
clang:asan

00:01:59

passed #1705996
amd64 linux
clang:buster:amd64

00:01:01

passed #1705999
amd64 libvirt
clang:freebsd11:amd64

00:01:07

passed #1706000
amd64 libvirt
clang:freebsd12:amd64

00:01:06

passed #1706001
amd64 libvirt
clang:openbsd:amd64

00:02:48

passed #1705994
amd64 linux
clang:tsan

00:01:15

passed #1705982
amd64 linux
gcc:alpine3.13:amd64

00:01:00

passed #1705991
amd64 linux
gcc:asan

00:01:36

passed #1705986
amd64 linux
gcc:buster:amd64

00:00:49

passed #1705983
amd64 linux
gcc:centos7:amd64

00:00:54

passed #1705984
amd64 linux
gcc:centos8:amd64

00:00:54

passed #1705990
amd64 linux
gcc:focal:amd64

00:00:55

passed #1705995
amd64 linux
gcc:mutexatomics

00:00:55

passed #1705988
amd64 linux
gcc:out-of-tree

00:00:54

passed #1705987
amd64 linux
gcc:sid:amd64

00:01:04

passed #1705997
amd64 linux
gcc:softhsm2.4

00:00:56

passed #1705998
amd64 linux
gcc:softhsm2.6

00:00:46

passed #1705985
amd64 linux
gcc:stretch:amd64

00:01:04

passed #1705993
amd64 linux
gcc:tsan

00:01:04

passed #1705989
amd64 linux
gcc:tumbleweed:amd64

00:00:57

passed #1706002
amd64 windows
msvc:windows:amd64

00:01:05

 
  Unit
canceled #1706012
amd64 linux
unit:clang:asan

00:02:07

passed #1706016
amd64 linux
unit:clang:buster:amd64

00:01:21

passed #1706019
amd64 libvirt
unit:clang:freebsd11:amd64

00:01:58

passed #1706020
amd64 libvirt
unit:clang:freebsd12:amd64

00:01:53

canceled #1706021
amd64 libvirt
unit:clang:openbsd:amd64

00:01:21

canceled #1706014
amd64 linux
unit:clang:tsan

00:02:00

passed #1706003
amd64 linux
unit:gcc:alpine3.13:amd64

00:01:22

canceled #1706011
amd64 linux
unit:gcc:asan

00:02:19

passed #1706007
amd64 linux
unit:gcc:buster:amd64

00:02:22

passed #1706004
amd64 linux
unit:gcc:centos7:amd64

00:01:18

passed #1706005
amd64 linux
unit:gcc:centos8:amd64

00:01:19

passed #1706010
amd64 linux
unit:gcc:focal:amd64

00:01:25

passed #1706015
amd64 linux
unit:gcc:mutexatomics

00:01:24

passed #1706008
amd64 linux
unit:gcc:sid:amd64

00:01:20

passed #1706017
amd64 linux
unit:gcc:softhsm2.4

00:01:15

passed #1706018
amd64 linux
unit:gcc:softhsm2.6

00:01:21

passed #1706006
amd64 linux
unit:gcc:stretch:amd64

00:00:12

canceled #1706013
amd64 linux
unit:gcc:tsan

00:02:17

passed #1706009
amd64 linux
unit:gcc:tumbleweed:amd64

00:01:22

 
  System
canceled #1706031
amd64 linux
system:clang:asan

00:00:39

canceled #1706035
amd64 linux
system:clang:buster:amd64

00:00:08

canceled #1706038
amd64 libvirt
system:clang:freebsd11:amd64

00:03:12

canceled #1706039
amd64 libvirt
system:clang:freebsd12:amd64

00:03:12

canceled #1706033
amd64 linux
system:clang:tsan

00:00:31

canceled #1706022
amd64 linux
system:gcc:alpine3.13:amd64

00:01:32

canceled #1706030
amd64 linux
system:gcc:asan

00:00:46

canceled #1706026
amd64 linux
system:gcc:buster:amd64

canceled #1706023
amd64 linux
system:gcc:centos7:amd64

00:01:17

canceled #1706024
amd64 linux
system:gcc:centos8:amd64

00:01:10

canceled #1706029
amd64 linux
system:gcc:focal:amd64

00:00:55

canceled #1706034
amd64 linux
system:gcc:mutexatomics

00:00:16

canceled #1706027
amd64 linux
system:gcc:sid:amd64

00:01:02

canceled #1706036
amd64 linux
system:gcc:softhsm2.4

canceled #1706037
amd64 linux
system:gcc:softhsm2.6

canceled #1706025
amd64 linux
system:gcc:stretch:amd64

00:01:02

canceled #1706032
amd64 linux
system:gcc:tsan

00:00:32

canceled #1706028
amd64 linux
system:gcc:tumbleweed:amd64

00:01:01

 
  Docs
canceled #1706040
amd64 linux
docs

 
  Postcheck
canceled #1706044
amd64 linux
cppcheck

canceled #1706041
amd64 linux
flake8

canceled #1706045
amd64 linux
gcov

canceled #1706042
amd64 linux
pylint

canceled #1706043
amd64 linux
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