client: Fix typo in doscstring.

caucase/client.py

@@ -60,7 +60,7 @@ class CaucaseClient(object):
   @classmethod
   def updateCAFile(cls, url, ca_crt_path):
     """
-    Bootstrap anf maintain a CA file up-to-date.
+    Bootstrap and maintain a CA file up-to-date.
 
     url (str)
       URL to caucase, ending in eithr /cas or /cau.