[vinagre] Let the user cancel the FreeRDP auth dialog

[David King <davidk src gnome org>]

commit e41759e91f80c8dfebd4424373c7bf201fb10bf9
Author: Guido Aulisi <guido aulisi gmail com>
Date:   Wed Nov 8 09:05:16 2017 +0100

    Let the user cancel the FreeRDP auth dialog
    
    https://gitlab.gnome.org/GNOME/vinagre/merge_requests/2

 plugins/rdp/vinagre-rdp-tab.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/plugins/rdp/vinagre-rdp-tab.c b/plugins/rdp/vinagre-rdp-tab.c
index b731f9b..5b98c24 100644
--- a/plugins/rdp/vinagre-rdp-tab.c
+++ b/plugins/rdp/vinagre-rdp-tab.c
@@ -1218,7 +1218,7 @@ open_freerdp (VinagreRdpTab *rdp_tab)
           init_freerdp (rdp_tab);
         }
     }
-  while (!success && authentication_errors < 3);
+  while (!success && !cancelled && authentication_errors < 3);
 
   if (!success)
     {