Remove now-unused dispatches

src/components/structures/MatrixChat.js

@@ -1331,13 +1331,6 @@ module.exports = React.createClass({
         cli.sendEvent(roomId, event.getType(), event.getContent()).done(() => {
             dis.dispatch({action: 'message_sent'});
         }, (err) => {
-            if (err.name === 'UnknownDeviceError') {
-                dis.dispatch({
-                    action: 'unknown_device_error',
-                    err: err,
-                    room: cli.getRoom(roomId),
-                });
-            }
             dis.dispatch({action: 'message_send_failed'});
         });
     },

src/components/structures/RoomView.js

@@ -932,11 +932,7 @@ module.exports = React.createClass({
             file, this.state.room.roomId, MatrixClientPeg.get(),
         ).done(undefined, (error) => {
             if (error.name === "UnknownDeviceError") {
-                dis.dispatch({
-                    action: 'unknown_device_error',
-                    err: error,
-                    room: this.state.room,
-                });
+                // Let the staus bar handle this
                 return;
             }
             const ErrorDialog = sdk.getComponent("dialogs.ErrorDialog");