fix(xapi/task_create): remove duplicate [XO] prefix

Found while investigating xoa-support#3553

@xen-orchestra/xapi/src/task.js

@@ -2,7 +2,9 @@ const ignoreErrors = require('promise-toolbox/ignoreErrors')
 
 module.exports = class Task {
   create(name = 'untitled task', description) {
-    return this.createTask(`[XO] ${name}`, description)
+    // don't call `this.createTask` which might be overriden by
+    // child class and already has the [XO] prefix
+    return super.createTask(`[XO] ${name}`, description)
   }
 
   destroy(ref) {