dixie: drop uid/gid from rsyncd modules — daemon runs as dropsonde via SSH, setgroups() fails otherwise

hw/dixie/analysis.nix

@@ -57,9 +57,10 @@ in
     # --- rsync daemon-over-ssh for the sync key --------------------------------
     # The dropsonde sync key's forced command runs `rsync --server --daemon`
     # against this config: two write-only modules rooted at the dropsonde2
-    # subdirs. use chroot = false so /srv paths resolve directly; uid/gid
-    # force the transfer to run as dropsonde. lock file is a global rsyncd
-    # parameter, so it sits at file scope (not per-module).
+    # subdirs. use chroot = false so /srv paths resolve directly; the daemon
+    # runs as dropsonde (the SSH user), so no uid/gid — setting them would
+    # make the non-root daemon fail at setgroups(). lock file is a global
+    # rsyncd parameter, so it sits at file scope (not per-module).
     environment.etc."rsyncd-dropsonde.conf".text = ''
       lock file = /home/dropsonde/rsyncd.lock
 
@@ -67,16 +68,12 @@ in
           path = /srv/cold/dropsonde2
           read only = false
           use chroot = false
-          uid = dropsonde
-          gid = dropsonde
           max connections = 2
 
       [analysis]
           path = /srv/analysis/dropsonde2
           read only = false
           use chroot = false
-          uid = dropsonde
-          gid = dropsonde
           max connections = 2
     '';