nixos/libvirtd-service: fix for dnsmasq (dir perms 700 -> 755)

Fixes this:

Nov 09 16:18:54 nixos-laptop systemd[1]: Starting Libvirt Virtual Machine Management Daemon...
Nov 09 16:18:54 nixos-laptop dnsmasq[15809]: read /etc/hosts - 2 addresses
Nov 09 16:18:54 nixos-laptop dnsmasq[15809]: failed to load names from /var/lib/libvirt/dnsmasq/default.addnhosts: Permission denied
Nov 09 16:18:54 nixos-laptop dnsmasq[15809]: cannot read /var/lib/libvirt/dnsmasq/default.hostsfile: Permission denied
Nov 09 16:18:55 nixos-laptop systemd[1]: Started Libvirt Virtual Machine Management Daemon.

I don't understand the reason for the original 700 permission bits.
Apparently read-access is needed and Ubuntu also use 755 perms.

Use "chmod" instead of "mkdir -m" to set permissions because mkdir doesn't
modify permissions on existing directories.

1 files changed, 5 insertions, 2 deletions

diff --git a/nixos/modules/virtualisation/libvirtd.nix b/nixos/modules/virtualisation/libvirtd.nix
index d3884a503bc7..552441f6a62d 100644
--- a/nixos/modules/virtualisation/libvirtd.nix
+++ b/nixos/modules/virtualisation/libvirtd.nix
@@ -82,8 +82,11 @@ in
             mkdir -p /var/log/libvirt/qemu -m 755
             rm -f /var/run/libvirtd.pid
 
-            mkdir -p /var/lib/libvirt -m 700
-            mkdir -p /var/lib/libvirt/dnsmasq -m 700
+            mkdir -p /var/lib/libvirt
+            mkdir -p /var/lib/libvirt/dnsmasq
+
+            chmod 755 /var/lib/libvirt
+            chmod 755 /var/lib/libvirt/dnsmasq
 
             # Libvirt unfortunately writes mutable state (such as
             # runtime changes to VM, network or filter configurations)