Don’t send the experimental-features to the daemon

The experimental features are, well, experimental, and shouldn’t be
carelessly and transparently enabled.
Besides, some (`ca-derivations` at least) need to be enabled at startup
in order to work properly.
So it’s better to just require that daemon be started with the right
`experimental-features` option.

Fix #5017

src/libstore/remote-store.cc

@@ -222,6 +222,7 @@ void RemoteStore::setOptions(Connection & conn)
         overrides.erase(settings.buildCores.name);
         overrides.erase(settings.useSubstitutes.name);
         overrides.erase(loggerSettings.showTrace.name);
+        overrides.erase(settings.experimentalFeatures.name);
         conn.to << overrides.size();
         for (auto & i : overrides)
             conn.to << i.first << i.second.value;