Get VM IP again when getting screenshot fails (#215)

In rare cases, the IP of the VM changes after it launches. We can get the IP every time we retry to ensure the correct connection.

desktop_env/providers/vmware/manager.py

@@ -256,6 +256,8 @@ def _install_vm(vm_name, vms_dir, downloaded_file_name, os_type, original_vm_nam
 
     # Try downloading the screenshot until successful
     while not download_screenshot(vm_ip):
+        # Try to get the IP again in case it has changed
+        vm_ip = get_vm_ip(vm_path)
         logger.info("Check whether the virtual machine is ready...")
 
     logger.info("Virtual machine is ready. Start to make a snapshot on the virtual machine. It would take a while...")