store: keys_at tells no map from an empty one

registry::exists counted any value at _continuum/users as a registry;
keys_at answers None where there is no map, and its users (records,
members, forget records, remakes) say what they make of it.

Auth plan M1 (fix).

1 files changed, 2 insertions, 2 deletions

diff --git a/src/remake/delta.rs b/src/remake/delta.rs
index 638231c..6864c4d 100644
--- a/src/remake/delta.rs
+++ b/src/remake/delta.rs
@@ -242,8 +242,8 @@ fn replay_path(
     // Replacing an ancestor of the protocol metadata as a whole would clobber it; replay
     // its children one by one instead.
     if contains_protocol_path(path) {
-        let mut keys = store::keys_at(src, path).unwrap_or_default();
-        keys.extend(store::keys_at(dst, path).unwrap_or_default());
+        let mut keys = store::keys_at(src, path).ok().flatten().unwrap_or_default();
+        keys.extend(store::keys_at(dst, path).ok().flatten().unwrap_or_default());
         keys.sort();
         keys.dedup();
         for key in keys {