Revert "Fork vobject"

This reverts commit 126a31c82a.

radicale/__init__.py

@@ -49,7 +49,7 @@ from http import client
 from urllib.parse import unquote, urlparse
 from xml.etree import ElementTree as ET
 
-import radicale_vobject as vobject
+import vobject
 
 from radicale import auth, config, log, rights, storage, web, xmlutils
 

radicale/storage.py

@@ -44,7 +44,7 @@ from math import log
 from random import getrandbits
 from tempfile import NamedTemporaryFile, TemporaryDirectory
 
-import radicale_vobject as vobject
+import vobject
 
 if sys.version_info >= (3, 5):
     # HACK: Avoid import cycle for Python < 3.5