fix typo

Author: jaketclarke

office365/sharepoint/principal/principal.py

@@ -56,7 +56,7 @@ def is_hidden_in_ui(self):
 
     @property
     def principal_type(self):
-        """Gets the login name of the principal.
+        """Gets the type of the principal.
 
         :rtype: int or None
         """