face: fire onFail event on WebSocket and Ethernet face close

Change-Id: I3d24c7b2e5003253ff04dab68ec1a2cb37b7d023
Refs: #1637
diff --git a/daemon/face/websocket-face.cpp b/daemon/face/websocket-face.cpp
index 4712cfc..5dfe516 100644
--- a/daemon/face/websocket-face.cpp
+++ b/daemon/face/websocket-face.cpp
@@ -64,6 +64,8 @@
       m_closed = true;
       websocketpp::lib::error_code ecode;
       m_server.close(m_handle, websocketpp::close::status::normal, "closed by nfd", ecode);
+
+      onFail("Face closed");
     }
 }