On Debian systems guix-daemon is provided in /usr/bin, use that one.

Index: guix-debian/etc/init.d/guix-daemon.in
===================================================================
--- guix-debian.orig/etc/init.d/guix-daemon.in
+++ guix-debian/etc/init.d/guix-daemon.in
@@ -11,7 +11,7 @@
 
 set -e
 mkdir -p "/var/run"
-if [ ! -f "@localstatedir@/guix/profiles/per-user/root/current-guix/bin/guix-daemon" ]
+if [ ! -f "/usr/bin/guix-daemon" ]
 then
   exit 5
 fi
