forgot part of the config serializer fix checkin

BizHawk.MultiClient/ConfigService.cs

@@ -19,6 +19,7 @@ namespace BizHawk.MultiClient
 					using (var reader = file.OpenText())
 					{
 						var s = new JsonSerializer();
+						s.SuppressMissingMemberException = true;
 						var r = new JsonReader(reader);
 						config = (T)s.Deserialize(r, typeof(T));
 					}