[PATCH nixpkgs] spectrumPackages.makeRootfs: fix messagebus group

[Alyssa Ross <hi@alyssa.is>]

/etc/passwd set the messagebus user's primary group to 1, but there
was no group with that id in /etc/group.  The messagebus group had id 4.
The 4 comes from NixOS.  I think it's probably a good idea to use the
same user and group ids where possible -- there's no particular reason
to diverge -- so let's fix it in /etc/passwd instead of changing the
id in /etc/group to 1.

And while we're here, for consistency, let's change the user id of
messagebus to 4 as well, so that's consistent with NixOS as well.
I don't think the user ID is used anywhere else.

This fixes the DBus "Permission denied" errors that have been showing
up in vm-net since forever (but never seemed to cause any real harm...).
---
 pkgs/os-specific/linux/spectrum/rootfs/etc/passwd | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pkgs/os-specific/linux/spectrum/rootfs/etc/passwd b/pkgs/os-specific/linux/spectrum/rootfs/etc/passwd
index c76fb8f2a99..ddb1f854a6e 100644
--- a/pkgs/os-specific/linux/spectrum/rootfs/etc/passwd
+++ b/pkgs/os-specific/linux/spectrum/rootfs/etc/passwd
@@ -1,3 +1,3 @@
 root:x:0:0:System administrator:/:/bin/sh
-messagebus:x:1:1:D-Bus system message bus daemon user:/run/dbus:/bin/sh
+messagebus:x:4:4:D-Bus system message bus daemon user:/run/dbus:/bin/sh
 user:x:1000:1000:User:/:/bin/sh
-- 
2.31.0