Fix cluster crash w/ config sync

refs #5212

lib/remote/apilistener-filesync.cpp

@@ -283,8 +283,8 @@ Value ApiListener::ConfigUpdateHandler(const MessageOrigin::Ptr& origin, const D
 	}
 
 	Log(LogInformation, "ApiListener")
-	    << "Applying config update from endpoint '" << origin->FromClient->GetEndpoint()->GetName() << "' of zone  '"
+	    << "Applying config update from endpoint '" << origin->FromClient->GetEndpoint()->GetName()
-	    << origin->FromZone->GetName() << "'";
+	    << "' of zone '" << GetFromZoneName(origin->FromZone) << "'.";
 
 	Dictionary::Ptr updateV1 = params->Get("update");
 	Dictionary::Ptr updateV2 = params->Get("update_v2");

lib/remote/apilistener.cpp

@@ -1245,3 +1245,19 @@ bool ApiListener::IsHACluster(void)
 	return zone->IsSingleInstance();
 }
 
+/* Provide a helper function for zone origin name. */
+String ApiListener::GetFromZoneName(const Zone::Ptr& fromZone)
+{
+	String fromZoneName;
+
+	if (fromZone) {
+		fromZoneName = fromZone->GetName();
+	} else {
+		Zone::Ptr lzone = Zone::GetLocalZone();
+
+		if (lzone)
+			fromZoneName = lzone->GetName();
+	}
+
+	return fromZoneName;
+}

lib/remote/apilistener.hpp

@@ -99,6 +99,7 @@ public:
 	static void UpdateObjectAuthority(void);
 
 	static bool IsHACluster(void);
+	static String GetFromZoneName(const Zone::Ptr& fromZone);
 
 protected:
 	virtual void OnConfigLoaded(void) override;