provision for dbus timeouts

gui/src/main/groovy/com/muwire/gui/linux/DBUSNotifyService.groovy

@@ -40,7 +40,8 @@ class DBUSNotifyService {
             Variant<String> variant = new Variant(soundName)
             hints.put("sound-name", variant)
         }
-        UInt32 rv = NOTIFICATIONS.Notify("MuWire", // app name 
+        try {
+            NOTIFICATIONS.Notify("MuWire", // app name 
                     new UInt32(0L), // replaces
                     "", // no icon
                     summary, // summary
@@ -48,5 +49,6 @@ class DBUSNotifyService {
                     Collections.emptyList(), // actions
                     hints, // hints
                     -1) // expire timeout
+        } catch (NoReply ignore) {}
     }
 }