message: Handle signals in null runtime
diff: @@ -29,20 +29,20 @@ class NullRuntime implements IRuntime {
  }
  public prepare(message: ISequencedDocumentMessage, local: boolean): Promise<any> {
  - return Promise.reject("Null chaincode should not receive messages");
  + return Promise.reject("Null runtime should not receive messages");
  }
  public process(message: ISequencedDocumentMessage, local: boolean, context: any) {
  - throw new Error("Null chaincode should not receive messages");
  + throw new Error("Null runtime should not receive messages");
  }
  public postProcess(message: ISequencedDocumentMessage, local: boolean, context: any): Promise<void> {
  - return Promise.reject("Null chaincode should not receive messages");
  + return Promise.reject("Null runtime should not receive messages");
  }
  public processSignal(message: any, local: boolean) {
  - // todo (mdaumi): We might want to buffer signals before transitioning.
  - return Promise.reject("Null chaincode should not receive signals");
  + // Null runtime can receive signals but it's okay to miss those.
  + return;
  }
  }
  