Remove all the device_id setting from the JS SDK

As discussed, this makes things quite complicated, so conclusion is that's better to just let the app do this.

lib/client.js

@@ -2423,32 +2423,11 @@ MatrixClient.prototype.register = function(username, password,
  * @return {module:http-api.MatrixError} Rejects: with an error response.
  */
 MatrixClient.prototype.registerRequest = function(data, kind, callback) {
-    var request_data = {};
-
-    // only add these if the app is sending something other than auth data
-    // subsequent calls to register with the same session will
-    // overwrite the parameters if any are passed, so it's important
-    // that if the app give no data, we send no data.
-    var number_of_params = Object.keys(data).length;
-    if (data.auth) {
-        --number_of_params;
-    }
-    if (number_of_params > 0) {
-        request_data = {
-            device_id: this.deviceId,
-            initial_device_display_name: this.defaultDeviceDisplayName,
-        };
-    }
-    // merge data into request_data
-    for (var k in data) {
-        if (data.hasOwnProperty(k)) { request_data[k] = data[k]; }
-    }
-
     var params = {};
     if (kind) { params.kind = kind; }
 
     return this._http.request(
-        callback, "POST", "/register", params, request_data
+        callback, "POST", "/register", params, data
     );
 };