pkgupdate: fix --no-reboot causing reboot

In rewrite to argp the --no-reboot and --reboot-required options were
mangled together and that meant that reboot was happening always when
reboot was disabled. How unfortunate.
7 jobs for v63.0.3 in 8 minutes and 36 seconds (queued for 37 seconds)
latest
Status Job ID Name Coverage
  Test
passed #256098
cppcheck

00:00:52

passed #256099
luacheck

00:00:52

passed #256096
system-tests

00:01:46

passed #256097
system-valgrind-tests

00:04:26

passed #256094
unit-tests

00:01:30

passed #256101
unit-valgrind-tests

00:04:00

failed #256095
unit-valgrind-tests

00:03:50