pid1: propagate the original command line when reexecuting
When we reexec the manager in a container, we lose configuration settings on
the kernel command line:
$ systemd-nspawn -M rawhide -b systemd.status-unit-format=name systemd.show-status=yes
...
# tr '\0' ' '
/usr/lib/systemd/systemd systemd.status_unit_format=combined systemd.show-status=yes
# sudo systemctl daemon-reexec
# tr '\0' ' '
/usr/lib/systemd/systemd --system --deserialize 20
This means that after daemon-reexec, the settings that we gain from the
commandline are reset to defaults.
So let's reeexecute with the original arguments copied over, modulo some
filtering.
(cherry picked from commit 846f1da465beda990c1c01346311393f485df467)