NXDRIVE-409: Don't fall back on basic auth if startup page request returns 500 (seems to happen in some cases of SSL error)

Author: ataillefer

nuxeo-drive-client/nxdrive/wui/settings.py

@@ -153,7 +153,7 @@ def web_authentication(self, local_folder, server_url, engine_name):
             # Connect to startup page
             status = self._connect_startup_page(server_url)
             # Server will send a 401 in case of anonymous user configuration
-            if status < 400 or status == 401:
+            if status < 400 or status in (401, 500):
                 # Page exists, let's open authentication dialog
                 engine_name = unicode(engine_name)
                 if engine_name == '':