[lynda] Fix non-ASCII logins/passwords on python 2

youtube_dl/extractor/lynda.py

@@ -30,8 +30,8 @@ class LyndaBaseIE(InfoExtractor):
             return
 
         login_form = {
-            'username': username,
+            'username': username.encode('utf-8'),
-            'password': password,
+            'password': password.encode('utf-8'),
             'remember': 'false',
             'stayPut': 'false'
         }