nixos/systemd-stage-1: follow systemd /run propagation

We currently bypass systemd's switch-root logic by premounting
/sysroot/run. Make sure to propagate its sub-mounts with the recursive
flag, in accordance with the default switch-root logic.

This is required for creds at /run/credentials to survive the transition
from initrd -> host.

Changed files
+1 -1
nixos
modules
system
boot
systemd
+1 -1
nixos/modules/system/boot/systemd/initrd.nix
···
{
where = "/sysroot/run";
what = "/run";
-
options = "bind";
+
options = "rbind";
unitConfig = {
# See the comment on the mount unit for /run/etc-metadata
DefaultDependencies = false;