fix(xo-server/Xapi#_importOvaVm): userdevice must be string not a number (#4232)

Fixes xoa-support#1479

CHANGELOG.unreleased.md

@@ -11,6 +11,7 @@
 - [Charts] Fixed the chart lines sometimes changing order/color (PR [#4221](https://github.com/vatesfr/xen-orchestra/pull/4221))
 - Prevent non-admin users to access admin pages with URL
 - [Upgrade] Fix alert before upgrade while running backup jobs (PR [#4235](https://github.com/vatesfr/xen-orchestra/pull/4235))
+- [Import] Fix import OVA files (PR [#4232](https://github.com/vatesfr/xen-orchestra/pull/4232))
 
 ### Released packages
 

packages/xo-server/src/xapi/index.js

@@ -1398,7 +1398,7 @@ export default class Xapi extends XapiBase {
         $defer.onFailure(() => this._deleteVdi(vdi.$ref))
 
         return this.createVbd({
-          userdevice: disk.position,
+          userdevice: String(disk.position),
           vdi,
           vm,
         })