fixed potential typo

Change-Id: I5f58f4dfe76c1c5b45c76bc122e0e891029a304c

jams-server/src/main/java/net/jami/jams/server/servlets/api/install/InstallLastStepServlet.java

@@ -40,6 +40,6 @@ public class InstallLastStepServlet extends HttpServlet {
         resp.setHeader("Access-Control-Allow-Origin", JamsCA.serverDomain);
         HashMap<String,String> payload = new HashMap<>();
         payload.put("uri",CachedObjects.endpoint);
-        resp.getOutputStream().write(JsonStream.serialize(resp).getBytes());
+        resp.getOutputStream().write(JsonStream.serialize(payload).getBytes());
     }
 }