[FIX] Tokens: Return the csrf token, when such a token is requested

With the new token system, most of the token names are now 'csrf'
tokens. So if the token name is unknown it uses a csrf token, but it
still looks for the original token name, which is of course not
present.

Change-Id: I38e326c0f5382a585fba11bc6cbfba1a3dffaca5

pywikibot/site.py

@@ -1185,9 +1185,16 @@ class TokenWallet(object):
     def __init__(self, site):
         self.site = site
         self.site._tokens = {}
+        # TODO: Fetch that from the API with paraminfo
+        self.special_names = set(['deleteglobalaccount', 'patrol', 'rollback',
+                                  'setglobalaccountstatus', 'userrights',
+                                  'watch'])
 
     def __getitem__(self, key):
         storage = self.site._tokens.setdefault(self.site.user(), {})
+        if (LV(self.site.version()) >= LV('1.24wmf19')
+                and key not in self.special_names):
+            key = 'csrf'
         if key not in storage:
             self.site.preload_tokens([key])
         return storage[key]
@@ -2295,11 +2302,7 @@ def preload_tokens(self, types):
                 data = api.Request(site=self, action='tokens',
                                    type='|'.join(types)).submit()
             else:
-                # TODO: Fetch that from the API with paraminfo
-                special_names = set(['deleteglobalaccount', 'patrol', 'rollback',
-                                     'setglobalaccountstatus', 'userrights',
-                                     'watch'])
-                new_tokens = [token if token in special_names else 'csrf'
+                new_tokens = [token if token in self.tokens.special_names else 'csrf'
                               for token in types]
                 data = api.Request(action='query', meta='tokens',
                                    type='|'.join(new_tokens)).submit()